100-4 Error Code (SPN 100 / FMI 4) Troubleshooting Guide

The error code 100-4 tends to pop up on big commercial trucks and industrial vehicles like forklifts. You might see it as SPN 100/FMI 4 on your Cummins’ display. Or error code 100-4 blinking on your Yale or Hyster forklift. Either way, it’s pointing to an issue with oil pressure. Specifically, low oil pressure in the engine.

So if you see that 100-4, it means the oil isn’t flowing strongly enough to properly lubricate all the moving parts under the hood. When the oil pressure drops, the oil can’t do its job keeping the pistons, valves, and bearings happily sliding and turning. The engine strains and struggles, and over time the damage builds up.

The code 100-4 illuminates to warn the driver there’s a problem that needs addressing fast. If left unfixed, the consequences can be dire — busted gaskets, seized pistons, worn out bearings, and sometimes complete engine breakdown. But with prompt troubleshooting, the root cause can be found and resolved before costly repairs are needed.

The good news is this post will provide a complete troubleshooting guide for fault code 100-4. I’ll walk you through how to track down the root cause and get that oil flowing safely again.

SPN 100 FMI 4 Error Code
SPN 100 / FMI 4 error code, also known as 100-4 fault code, displayed on vehicle’s dashboard.

Why & When 100-4 Fault Code Shows Up In Your Vehicle?

The 100-4 or SPN 100/FMI 4 error message pops up on the dashboard display when the engine’s electronic control unit (ECU) senses low oil pressure. The ECU is the electronic brain monitoring all aspects of engine operation, so it takes oil pressure very seriously. If the oil pressure drops too low, there will be a lack of oil circulation to keep the engine lubricated. This might cause grinding of the engine parts and excessive wear and tear to them.

When the ECU detects the oil pressure has fallen below the normal range, it will trigger the 100-4 code to appear on your dashboard display to warn you there’s a problem. At this point, the lack of oil flow is not good for your engine and continued driving could cause permanent damage.

There are a few possible causes for low oil pressure that would lead to this code appearing. It could be a faulty oil pressure sensor or wiring, a short in the sensor circuit, or the oil pressure sensor itself going bad.

💡 Error Code 100-4 (SPN 100 / FMI 4) vs Error Code 100-3 (SPN 100 / FMI 3)

Error code 100-4, also referred to as SPN 100 / FMI 4, indicates a situation of low oil pressure in the forklift or the truck’s engine.

On the other hand, error code 100-3, also known as SPN 100 / FMI 4, signifies high oil pressure in the forklift or the truck’s engine.

Both error codes share a common characteristic in that they identify abnormalities in the oil pressure of the vehicle’s engine. However, they differ in terms of the specific issue they highlight. Error code 100-4 targets low oil pressure, while error code 100-3 targets high oil pressure.

The diagnostic and troubleshooting process is consistent for both fault codes. In the case of 100-4, verify that your forklift engine’s oil pressure falls within the standard range. For 100-3, ensure the oil pressure isn’t higher than the standard range.

Possible Causes

There are five possible reasons why the error code 100-4 may show up on your Cummins, Detroit Diesel, or Yale equipment. I’ll explain each of these potential issues in detail below:

1). Faulty Engine Harness Connecting the Oil Pressure Sensor

The engine harness connecting the oil pressure sensor could be the reason behind error code 100-4. It is possible that the connector has pushed back or expanded pins, bent or broken pins, or corroded pins. These issues can disrupt the connection between the sensor and the engine harness, causing the error code to appear.

2). Moisture in or on the Connector

Another potential cause of error code 100-4 is moisture in or on the connectors connecting to the oil pressure sensor. Moisture can interfere with the electrical signals being transmitted through the connector, leading to an erroneous reading from the oil pressure sensor. This can trigger the error code and indicate a problem with the engine harness.

3). Missing or Damaged Seals

Missing or damaged seals in the oil sensor’s harness can also contribute to error code 100-4. Seals are crucial for maintaining a proper connection and preventing moisture or other contaminants from entering the connector. If these seals are missing or damaged, it can compromise the integrity of the connection and trigger the error code.

4). Low Engine Oil

The ‘100-4’ fault code could also be triggered due to low oil levels in your vehicle’s engine. Oil’s what keeps your engine’s insides running smooth, and without enough of it, you’ll grind those parts to dust in no time.

Now oil levels drop for a couple reasons. Maybe you’ve sprung a leak somewhere, in which case you’ll want to get under there and find it quick before you’re bone dry. But more often it’s just that you’ve gone too long between oil changes, or burned some off driving too hard. Whatever the case, best check your levels pronto.

Checking your oil isn’t a complicated thing. Pop the hood, locate the dipstick – that’s the handle with the yellow top that says ‘oil’ on it. Pull it out, wipe it clean, slide it back in, then pull it out again. Check the markings on the end of the stick, see where the oil line is. If it’s low, time to add a quart or three.

Now, if that dipstick showed your oil was low, here’s what you do. Make sure you’ve got the right oil for your engine – check the manual if you’re unsure. Unscrew the oil fill cap and top it off a quarter quart at a time, rechecking the dipstick as you go. Keep adding small amounts until the level reads full. Replace the fill cap when you’re done.

5). Faulty Oil Pressure Sensor

The oil pressure sensor is usually a little metal cylinder with some wiring attached. It’s mounted somewhere on your engine block, immersed in the oil flow. When the oil is pumping strong and true, that sensor remains content and quiet. But if it detects oil pressure dropping too low, it hollers for help by triggering the SPN 100/FMI 4 code.

To check if your oil pressure sensor has gone faulty, first look for any visible damage to it. See if the wiring is frayed or disconnected, or if the sensor body itself is cracked or broken. You can also get a mechanical oil pressure gauge and compare the sensor’s reading to the gauge’s — if they differ by a fair amount, the sensor probably needs replacement.

Oil Pressure Sensor 100-4 Error fault code path selection
Fault Code 100-4 path on a Cummins truck.

Troubleshooting Guide

Troubleshooting error code 100-4 requires a thoughtful, step-by-step approach. We must not rush to complex diagnoses before testing the basics. Methodical troubleshooting reveals the root cause.

➜ Typically we’d start by checking the open circuit. Verify all connectors fit snug and no wires look damaged. Wiggle things around while watching for intermittent power loss. That sort of thing. Just common sense open circuit testing.

➜ Next we inspect the engine oil pressure sensor wiring. Unplug the sensor and check the harness and pins for corrosion or loose/broken connections. Ohm out the wires checking for shorts to ground or power. Replace damaged wires if needed. You get the idea – standard wiring diagnostics.

➜ Finally we test the oil pressure sensor itself. If no wiring faults appeared in the last step, replace the suspect sensor, clear any codes, and retest for proper operation. The new sensor should fix it if the wiring checks out.

Here’s a complete step-by-step troubleshooting guide for error code 100-4 or SPN 100/FMI4:

Step #1 – Inspecting the oil pressure switch and engine harness connector pins.

Turn the key switch OFF and disconnect the engine harness from the oil pressure switch. Inspect the oil pressure switch and the engine harness connector pins for the following:

  • Pushed back or expanded pins
  • Bent or broken pins
  • Corroded pins
  • Moisture in or on the connector
  • Missing or damaged seals
Are the pins damaged?
If not, go to the next step.If yes, repair or replace the oil pressure switch or the engine harness, whichever has damaged pins

Step #2 – Inspecting the engine harness and ECM connector pins.

Turn the key switch OFF and disconnect the engine harness from the ECM. Inspect the engine harness and the ECM connector pins for the following:

  • Pushed back or expanded pins
  • Bent or broken pins
  • Corroded pins
  • Moisture in or on the connector
  • Missing or damaged seals
Are the pins damaged?
If not, go to the next step.If yes, repair or replace the engine harness or ECM, whichever has damaged pins.

Step #3 – Inspecting an open circuit.

Turn the key switch OFF and disconnect the engine harness from the oil pressure switch. Disconnect the engine harness from the ECM.

Check for an open circuit. Measure the resistance from pin of the engine harness connector to the oil pressure switch connector.

Are the ohms within the standard range?
If yes, go to the next step.If not, replace the engine harness.

Step #4 – Inspecting a circuit to ground.

Turn the key switch OFF and disconnect the engine harness from the oil pressure switch. Disconnect the engine harness from the ECM.

Check for a short circuit to ground. Measure the resistance from the pin of the engine harness connector to engine block ground.

Are the ohms within the standard range?
If yes, go to the next step.If not, replace the engine harness.

Step #5 – Inspect for a short circuit from pin to pin.

Turn the key switch OFF and disconnect the engine harness from the ECM. Disconnect the engine harness from the oil pressure switch.

Check for a short circuit from pin to pin. Measure the resistance from the pin of the engine harness connector to all other pins in the engine harness connector.

Are the ohms within the standard range?
If yes, replace the oil pressure sensor.If not, replace the engine harness.

🚜 How to Find the Correct Pin to Measure Resistance?

Determining the correct pin to measure resistance in an engine harness can vary depending on the specific vehicle or equipment model. However, there are general steps you can follow to identify the correct pin:

1. Consult the Service Manual: The most reliable method is to refer to the service manual of the specific forklift or truck model you’re working on. The manual typically includes a wiring diagram that indicates the pin numbers and their functions.

2. Trace the Circuit: If you don’t have access to the service manual, you can trace the circuit from the oil pressure switch back to the engine harness connector. This may help you identify which pin corresponds to the oil pressure switch.

3. Use a Multimeter: Set your multimeter to the resistance (ohms) setting and test each pin in the engine harness connector until you find the one that shows continuity with the oil pressure switch connector. This is the pin you would measure for resistance.

Resolving Fault Code 100-4 or SPN 100/FMI 4 in Trucks and Forklifts

Getting fault code 100-4 on your Cummins truck or Yale Forklift?

No worries, we can figure this out. There’s a process to follow with a few key steps that should get us to the bottom of it.

Let me share the diagnosis steps so you know how to resolve this error code.

Fix #1: Do the cables connecting to the oil pressure sensor appear to be in good shape?

As an experienced mechanic, I always start by checking the connectors and wiring harness leading to the oil pressure sensor.

The oil pressure sensor’s wiring harness and connectors play a pivotal role in the accurate transmission of electrical signals and power to and from the oil pressure sensor.

Inside these connectors or switches attached to the oil pressure sensor are little metal pins that carry signals from the oil pressure sensor back to the forklift’s electronic control unit (ECU). The ECU processes these signals to monitor and adjust the forklift’s performance in real-time.

If a pin is bent or broken, it may still make contact but could deliver intermittent signals, leading to fluctuating readings that do not represent the actual oil pressure.

This causes the ECU to register an abnormal oil pressure error due to the lack of data.

So the first step when it comes to troubleshooting fault code 100-4 is to turn the key switch OFF and disconnect the engine harness from the oil pressure switch. And then Inspect the oil pressure switch and the engine harness connector pins for the following:

Bent or Broken Pins: Connector pins on the oil pressure sensor’s harness are responsible for transmitting electrical signals from the sensor to the ECU. Bent or broken pins can disrupt this signal, leading to inaccurate oil pressure readings. This can cause the ECU to misinterpret the oil pressure, potentially resulting in improper engine adjustments or a failure to alert when oil pressure is out of the normal range.

Pushed Back or Expanded Pins: If the pins are pushed back or expanded, they may not make proper contact with the corresponding receptacles in the connector. This can lead to intermittent or weak signals, causing fluctuating oil pressure readings that confuse the ECU and lead to erratic engine behavior.

Corroded Pins: Corrosion on the pins can be caused by exposure to moisture or chemicals, leading to increased electrical resistance. High resistance can weaken the signal from the sensor, causing the ECU to receive incorrect information about the engine’s oil pressure.

Moisture in or on the Connector: Moisture can cause short-circuits or corrosion, both of which can interfere with the electrical signals passing through the connector. This can result in the ECU receiving no signal or a faulty signal, which may trigger an oil pressure error.

Fix #2: Is there trouble with the EOP sensor circuit?

The error code 100-4 on a forklift means there’s trouble with the Engine Oil Pressure (EOP) sensor circuit.

When the oil pressure sensor circuit has an electrical short to ground, it sets off this code.

This circuit relays the oil pressure from the engine to the computer, so the computer knows if there’s enough juice lubricating all those churning parts. Oil pressure is key because without enough of it, the engine can’t lubricate itself properly. Parts grind and overheat.

Now a short to ground means somewhere along that wire path electricity is leaking straight to the body of the forklift rather than following the route to the computer. Could be a fray in the wires, the sensor itself gone kaput, or a loose connection letting the current sneak away.

When the oil pressure sensor circuit is short to ground, the sensor can send the wrong signals to the forklift’s computer. The computer might think there’s too little oil pressure when there’s really enough. Or it may get no signal at all.

If the forklift’s computer gets the wrong oil pressure readings, the engine won’t run right. The computer may think the oil pressure is too low to operate safely. So the engine could run rough or even shut off to avoid damage.

The fix here is to track down the short circuit. Check connections are tight, wires intact, and the sensor itself is in working order. The computer needs good intel to manage the engine properly. Once you get that oil pressure data flowing right again, the computer can relax and let the engine run as it should.

Fix #3: Has the voltage from the engine oil pressure switch dropped below the acceptable threshold?

Fault code 100-4 also means that the voltage from the engine oil pressure sensor has dipped below the acceptable threshold.

In simpler terms, the forklift’s ECU has detected that the voltage signal received from the engine oil pressure sensor is too low, which suggests that the oil pressure within the engine might be insufficient.

But why does this voltage system exist?

Well, it serves as a crucial monitoring mechanism to ensure that the engine oil pressure remains within the acceptable range. By measuring the voltage, the forklift can identify any potential issues with the engine’s oil pressure.

Typically, for most forklift models, the voltage range lies between 4.5 and 5.5 volts.

Talking in the context of the engine oil pressure’s voltage issue, the error code 100-4 could arise due to several reasons:

Firstly, the oil pressure sensor itself might be malfunctioning or have completely failed, resulting in the transmission of an incorrect low voltage signal. Additionally, there could be problems with the wiring connected to the oil pressure sensor, such as a short circuit or disconnection, causing a disruption in the voltage signal.

However, it is also essential to recognize that the engine could genuinely be experiencing low oil pressure. This can stem from various factors, including a low oil level, worn engine components, or even a faulty oil pump.

In some cases, the forklift may even enter a “limp mode,” where its performance is restricted to prevent any further damage. This serves as a protective measure, ensuring that the forklift is not operated under unfavorable conditions, which could lead to severe engine damage.

Therefore, it becomes imperative to address the issue promptly to prevent any further damage.

Fix #4: Are there any missing or damaged seals on the switch or harness?

Error code 100-4 on a forklift can be attributed to the absence or deterioration of seals within the oil pressure switch or the harness. When those seals start leaking or go missing, the oil doesn’t build up the pressure it needs, and the engine doesn’t get the oil it’s hankering for.

Without that oil pressure, your forklift’s engine can overheat right quick. The pistons and valves don’t get the lubrication they need and end up scraping themselves raw. It’s a sorry state of affairs, to be sure. Those seals and the harness are there to make sure the oil flows smooth and steady, keeping your engine running cool and clean.

There are several factors that can contribute to the damage or loss of these seals. For instance, regular wear and tear over time can cause deterioration, especially if the forklift is subject to demanding working conditions or insufficient maintenance. Additionally, accidental impact or mishandling during maintenance procedures can result in the seals becoming damaged or displaced.

The fix is simple. Replace those worn out seals with new ones, make sure they’re seated properly. Then that forklift will run clean as a whistle. Engine will fire right up, oil will flow smooth as silk, and voltage will be steady as the forklift goes!

Fix #5: Could the oil pressure sensor be malfunctioning?

The 100-4 fault code can also come up when there’s an issue with the oil pressure sensor in the engine. In most forklifts, the oil pressure switch sits on the engine block, typically below and to the right of the electronic control module. There are a few ways to check if the oil pressure sensor is working properly or not:

➜ A failing oil pressure sensor can make the engine noisy or the timing chain rattle. You’ll hear a low, metallic rattling from the engine, especially if the timing chain is fed oil and the tensioners lose pressure. The bad sensor isn’t detecting the oil pressure dropping, so the engine sounds off. The most surefire way is to manually check the oil pressure with a gauge. If the gauge shows good oil pressure but the dash light is on, it’s probably a bad sensor. 

➜ Sometimes a faulty oil pressure sensor leaks oil too, which you’ll spot around where the sensor sits. Oil can seep past the sensor’s bad seal, dripping onto the engine. A failing sensor may get oil on its body, a sign it’s leaking.

➜ Look for corrosion or damage on the sensor or its plug. Exposure to the elements in the engine bay can corrode the sensor, and physical harm can also cause issues.

Leakage in the oil pressure sensor
Sometimes a faulty oil pressure sensor has oil leakage inside and outside.

⛽ How To Check If The Oil Pressure Sensor Needs Replacement?

To check if your oil pressure switch has gone south, you’ll want to get your hands on an oil pressure testing kit.

Once you have the necessary tools for the job, start by locating the oil pressure switch, usually found on the engine block.

Loosen the switch, being careful not to strip the threads, then install the oil pressure testing gauge in its place.

Start up your forklift to circulate the oil, and check the reading on your gauge.

If it’s lower than the specification in your owner’s manual, you likely have a short circuit or a faulty harness. However, if the pressure is normal, you have a bad oil pressure switch and simply need to replace it to get back to work.


In conclusion, resolving the error code 100-4 in your forklift or truck is not always a straightforward fix. And often, it requires a bit of detective work to pinpoint the exact cause. Whether it’s a faulty harness, short-circuited wires, or an issue with the oil pressure sensor itself, each scenario demands a careful approach.

For some, the resolution might be as simple as replacing a worn-out harness that has seen better days. For others, it could involve tracing and repairing short circuits that are causing havoc in the electrical system. And then there are times when the oil pressure sensor is the culprit.

How did you resolve the fault code 100-4? Was it a matter of swapping out the harness, or did you find yourself untangling a web of electrical shorts? Or perhaps it was the oil pressure sensor that needed your attention. Share your experiences and solutions in the comments below.

Error Code 853 on Crown Pallet Jack: How To Fix This Fault Code?

Nothing slows down warehouse operations like an unexpected error code 853 on your go-to Crown pallet jack.

If you’ve ever seen the 853 code on the Crown Pallet Jack while shuttling pallets to and fro, take a deep breath.

Our forklift expert M.H Nizami has the inside scoop on what this code means and how to fix it.

What does the Error Code 853 mean on a Crown Pallet Jack?

Error code 853 on a Crown pallet jack indicates a throttle mismatch. This means the control system isn’t receiving consistent signals between the throttle position and the actual motor movement.

For example, you may try to accelerate forward but the jack sputters or even moves in reverse. Or the throttle seems “sticky” and is slow to respond as you speed up and slow down. Basically, the jack is confused about what you’re telling it to do with the throttle.

A Crown Pallet Jack displaying the 853 Error Code.

When error 853 pops up on the Crown Pallet Jack, you’ll likely experience jerky, inconsistent, or unexpected movement in the forward and reverse directions. The jack may hesitate before responding to throttle input, or it may take off faster than expected. This unpredictable behavior makes the pallet jack difficult to control and can potentially cause accidents.

The good news?

Some basic troubleshooting and maintenance can often fix error 853 on a Crown pallet jack.

Typical solutions include inspecting and cleaning the throttle potentiometer and associated wiring, checking for loose connections, replacing damaged wires, or replacing the potentiometer if faulty.

Our expert will walk you through these steps to get your Crown jack back up and running smoothly. Keep reading for the full troubleshooting details!

Troubleshooting Error Code 853 on Crown Pallet Jack

There are various troubleshooting methods, depending on the underlying issue causing the error 853 on Crown pallet jacks. Some fixes like repairing short circuits in cable connections are quick, while replacing faulty potentiometers requires more technical work. The complexity of repairs for code 853 ranges from fast fixes to more intensive part swaps, so diagnosing the specific problem is key before beginning any troubleshooting.

➜ Replace Potentiometer or Throttle Card

  1. Remove the switch cap and disconnect the connectors.
  2. Replace the potentiometer or throttle card inside the grip.
  3. Reconnect and reassemble the switch cap.

➜ Replace Control Circuit Fuse (FU3)

  1. Check the FU3 fuse for damage.
  2. Test continuity with a multimeter.
  3. Replace with a new fuse if blown, addressing any underlying issues.

➜ Check Wiring for Opens or Shorts

  1. Inspect wiring from positive signal to CA205-3 and from B-NEG to CA205-2.
  2. Use a multimeter to test for continuity and shorts.
  3. Repair or replace damaged wires.

➜ Confirm Values in Tiller Throttle Menu

  1. Use the handset controller to access the Monitor menu.
  2. Navigate to the Tiller Throttle menu and check the Raw Tiller Throttle value.
  3. Replace the faulty throttle potentiometer if the value on Neutral is not 0.

➜ Check Harnesses and Connections

  1. Inspect wiring harnesses for damage, particularly at knuckle/pivot points.
  2. Apply DeoxIT Gold to connectors and recalibrate.
  3. Replace potentiometers if necessary, especially if stops are worn.

How To Fix Error Code 853 on Crown Pallet Jacks?

Error code 853 on the Crown pallet jack can be frustrating to deal with. Here we have shared the 5 tried-and-tested fixes to try for this fault code.

Fix #1: Replace The Potentiometer or Throttle Card

Error Code 853 on Crown pallet jacks typically results from malfunctioning components within the electronic handle. Specifically, the potentiometer and throttle control card are most likely to blame.

The potentiometer is a sensor that detects the angle of the twist grip and converts it into an electrical signal. This tells the motor how fast to drive the wheels. The throttle control card takes the potentiometer’s signal and regulates the motor speed.

If either component fails, you’ll get error 853 and probably issues with going forward or backward. The potentiometer might not sense the twist grip properly, so the throttle card doesn’t know how fast you want to go. Or the throttle card could be malfunctioning and unable to control the motor, even with a good signal.

These electronic parts are critical for smooth, variable speed control on modern Crown pallet jacks. Older jacks had simple switches, but the twist grip allows precise speed regulation. Losing this makes the jack frustrating to operate.

To fix Error Code 853 on a Crown Pallet Jack, you’ll need to remove the handle’s switch cap and unplug the connectors. Then open up the grip to access the potentiometer and throttle card. Once located, replace either or both components with new parts to resolve the error and restore full functionality to the pallet jack.

Potentiometer of Crown Pallet Jack
The potentiometer (POT) detects how much the handle is being moved and sends that information to the control system. This allows the pallet jack to respond accordingly and move in the desired direction.

👉 Replacing the Potentiometer:

Here’s a step-by-step guide to fix Crown Pallet Jack error code 853 by replacing the faulty potentiometer or throttle card:

1). Remove the switch cap – Start by unscrewing the bolts that attach the handle’s switch cap assembly to the pallet jack. This will allow you to detach the switch cap from the pallet jack handle so you can access the internal components.

2). Disconnect the electrical connectors – Once the switch cap is off, you’ll see cables and connectors that attach it to the internal electronics. Carefully remove these connectors so you can fully detach the switch cap assembly.

3). Take out the old potentiometer – Inside the switch cap you’ll find the potentiometer, which is the component that needs to be replaced. Remove the screws that hold the potentiometer in place so you can take it out.

Here’s how the Potentiometer on the Crown Pallet Jack looks like.

4). Install the new potentiometer – With the old potentiometer removed, put the new one in the same spot and secure it with screws. Make sure it is centered properly within the switch cap assembly.

5). Reconnect the electrical components – It’s tricky, but you’ll need to reconnect the cables and connectors to the new potentiometer in the same way they were attached originally. Take your time and be methodical here.

6). Reassemble the switch cap – With all the internal components back in place, you can now reattach the switch cap assembly to the pallet jack handle using the original bolts. Tighten everything back up and you should be good to go.

👉 Replacing the Throttle Card:

If simply replacing the potentiometer doesn’t resolve the 853 error code on your Crown pallet jack, then you need to replace the throttle card.

The throttle control card is responsible for regulating the speed and power of the pallet jack. It receives signals from the potentiometer and adjusts the motor’s output accordingly.

1). To do this, you’ll need to remove and open up the switch cap assembly on the handle (as explained above).

2). Inside, you’ll find a throttle card located right next to the potentiometer. The throttle card is a small, rectangular-shaped circuit board that controls the throttle input signal from the potentiometer. Over time, the solder joints and components on the card can fail, causing erratic throttle signals.

3). Carefully remove the old throttle card by unplugging the connector and unscrewing any mounting screws.

4). Install a new replacement throttle card, taking care to firmly seat the connector and secure the mounting screws.

5). Once the new throttle card is installed, reassemble the switch cap. With any luck, this should resolve that error code for good. Double-check that the throttle and speed control are working properly before putting your Crown pallet jack back into service.

Here’s how the throttle card on the Crown Pallet Jack’s handle cap assembly looks like.

Fix #2: Replace The Control Circuit Fuse (FU3)

An issue with the control circuit fuse can also cause Error Code 853 on the Crown Pallet Jack.

So make sure to check the condition of the control circuit fuse, also known as the FU3 fuse. This fuse provides power specifically to the pallet jack’s handle and control circuitry.

The FU3 fuse is typically located on the control panel or near the battery on the Crown Pallet Jack. It protects the control circuit from power surges and shorts. If the FU3 fuse is blown, it will cut power to the handle and prevent the pallet jack from operating properly, which can cause error code 853.

Here’s how to troubleshoot it:

1). Visually inspect the FU3 fuse for any signs of damage or a broken filament.

2). Use a multimeter to check for continuity through the fuse.

3). If the FU3 fuse is blown, replace it with an identical new fuse with the proper amperage rating. A blown fuse indicates there may be an underlying short or power issue in the control circuit that will need to be diagnosed and repaired.

4). Replacing the FU3 fuse may allow the pallet jack to operate normally again.

5). But if the error code returns, further electrical testing and troubleshooting will be required. Be sure to fully diagnose and repair any control circuit issues to prevent repeated fuse failure.

Fix #3: Check The Wiring For Any Opens or Shorts

When resolving error code 853 on a Crown pallet jack, you’ll need to check the wiring from the positive signal to CA205-3 and from B-NEG to CA205-2 for any openings or shorts.

CA205-3 and CA205-2 refer to specific pins on the motor controller circuit board that help regulate power to the electric drive motor. The positive signal wire provides power to CA205-3 while the B-NEG wire connects the motor to the ground via CA205-2.

If either of these wires is open (disconnected) or shorted (touching together or touching the ground), it can trigger the 853 error code and prevent the pallet jack’s motor from operating properly.

To check for open or shorted wires, first visually inspect the length of the wires for any obvious damage, cuts, or abrasions in the insulation that could cause a short. Use a multimeter set to continuity mode to test each wire end-to-end for continuity. If you find a break in continuity, that indicates an open wire. You can also use the multimeter to check for shorts between the wires or from each wire to a ground point.

If you confirm an open or short in either the positive signal or B-NEG wiring, you will need to repair or replace the damaged wire to restore proper operation and clear the 853 error code.

Fix #4: Confirm The Values In The Tiller Throttle Menu

Error code 853 can sometimes pop up due to changed value settings in the pallet jack’s computer system. To check if this is the culprit, you’ll need a handset controller for the pallet jack. Crown makes handset controllers that let you access the pallet jack’s computer menus and monitor values.

1). Using the handset, scroll down to the Monitor menu.

2). From there, go to the Tiller Throttle menu, and select Raw Tiller Throttle.

3). Check the value that appears. With the throttle in neutral, the value should be 0. As you move the throttle, the value should change accordingly.

If the values don’t seem right as you operate the throttle, then the likely cause is a faulty POT or potentiometer. The POT is what tells the computer the throttle position. When it goes bad, it can send incorrect values to the computer, resulting in error 853. Replacing the POT, also called the throttle potentiometer, will restore normal operation.

Fix #5: Check The Harnesses and Connections

Harness issues are very common on the old Crown pallet jack models. The wiring harnesses on these older jacks are prone to failure, causing error code 853.

Make sure to check down by the knuckle/pivot point for any wires that may have rubbed through. Also, spray some DeoxIT Gold on all the connectors on the circuit boards. DeoxIT is a contact cleaner, lubricant, and anti-oxidizing solution that can help improve electrical connections. After doing that, recalibrate and see if the code clears up.

If that doesn’t fix it, the potentiometers (POTs) are likely bad. The new replacement POTs come in a kit with new stops for the twist grip. The old stops can wear out which lets the POT rotate beyond its normal range, causing damage. You may need to replace the POT again if the stops are worn.

Most harness issues were fixed in later Crown models. But it helps to know exactly when the 853 code pops up – like only when turning one way or the other. On the older jacks, harnesses often rubbed through under the handle assembly, where they contact the frame. Also, check the harness at the handle stem pivot point. These failure points aren’t always obvious. Intermittent fuse blowing is also a sign of harness failure.

The key is to methodically check the harnesses and connections. DeoxIT and calibration may do the trick. If not, replacing the POT and stops is the next step. Later Crowns improved the harnesses so 853 is less common. But on those temperamental older models, harness, and POT issues are where I’d start troubleshooting.


In conclusion, resolving error code 853 on a Crown pallet jack demands a methodical approach that addresses a range of potential causes, from faulty components to wiring issues and beyond. By conducting thorough inspections and implementing the appropriate fixes, operators can restore optimal functionality to their pallet jacks and ensure smooth operations in their material handling tasks.

Thank you for reading! If you encounter any further issues or have additional questions, please feel free to leave your queries in the comment section below. Our pallet jack expert will be on hand to provide assistance and guidance.

Toyota Forklift Error Code E06-1, E06-2 Troubleshooting Guide

E06-1 and E06-2 on a Toyota Forklift are simply indicators that it’s time for a throttle check. Follow our expert advice for a hassle-free troubleshooting experience, and you’ll have your forklift performing at its best in no time.

Error Code E06-1 and E06-2 on Toyota Forklift: The 3 Main Causes

The best running forklift is thanks to knowing your codes. Remember that E06-1 or E06-2 on the Toyota’s dash is not to be ignored as they are your lift truck’s way of saying something urgent by waving a red flag. Let’s look at what these codes mean and which parts they relate to, so your forklift stays in tip-top condition.

An illustration of the portion related to Toyota Forklift Error Code E06-1 and E06-2.
An illustration of the portion related to Toyota Forklift Error Code E06-1 and E06-2.

1). Throttle Motor Issue:

The throttle motor in a forklift controls the airflow to the engine, which manages the engine’s power and speed. If there’s an issue with the throttle motor, your Toyota Forklift might show error codes E06-1 and E06-2. This problem can make the engine act up, reduce efficiency, or even totally lose power. That makes it hard to operate the forklift safely and effectively.

2). Wiring Harness Issue:

In forklifts, a wiring harness is the network of wires and connectors that send electrical signals and power through the vehicle. If there’s an issue with the harness, like damaged wires or loose connections, it can mess up communication between different forklift parts. This could set off the E06-1 and E06-2 error codes and could cause the electrical systems to partially or completely fail. That leads to operation problems and potential safety issues.

3). Engine Controller Issue:

The engine controller is basically the forklift’s computer. It manages different engine functions to keep everything running smoothly. An issue with the engine controller could make error codes E06-1 and E06-2 show up. This problem could lead to improper engine management, impacting performance, fuel efficiency, and emissions. In bad cases, it could stop the forklift from starting or make it stall while operating.

Resetting Guide

To resolve the error codes E06-1 or E06-2 on a Toyota Forklift, resetting the fault codes can often remedy the issue. However, if the errors continue to appear, it may indicate a malfunctioning throttle or wiring harness connectivity problem that requires troubleshooting.

Here’s how to reset an E06 error on a Toyota Forklift:

  1. The first step is to disconnect the negative battery terminal for at least 10 seconds. This resets the forklift’s computer system and clears any stored error codes.
  2. Next, disconnect the water inlet to parts G6 and AG1. Inspect these connections – they bring water into the system for cooling, so any blockages or leaks here can cause overheating issues that trigger an E06 code.
  3. Reconnect any loose connections. Make sure there’s no corrosion or damage.
  4. Reconnect the water inlet tubes and battery negative terminal.
  5. Then, turn the ignition key to the “ON” position to start the engine and check if any error codes are displayed.
  6. If no errors appear, the issue was likely a loose or corroded connector in the wiring harness. Connector issues can disrupt signals to the forklift’s computer and throttle, causing error codes. Tightening or cleaning the connectors should resolve the problem and prevent the error from returning.
  7. But if the E06 error remains, there is likely an internal issue with the throttle motor or wiring harness. Further troubleshooting of the throttle and harness circuits will be needed to pinpoint the root cause.

The key points are to first reset the error code, and then inspect the water inlet connections. If the error returns, it indicates a deeper issue that requires advanced troubleshooting of the throttle and wiring.

E06-1 and E06-2 Error Code Troubleshooting Guide

As shared above, error code E06-1 or E06-2 in most cases boils down to one of three components – the throttle motor, wiring harness, or engine control unit. The tricky part is figuring out which one. Instead of a shotgun approach, let’s walk through the step-by-step troubleshooting guide.

I’ll explain the telltale signs of each potential culprit, tests to perform, and how to zero in on the root cause. By working together to isolate the source of the problem, you can get your forklift operating optimally once again.

1). Throttle Motor Resistance Inspection

First up, you need to carry out a throttle motor inspection. This involves testing the motor itself separately from the rest of the system.

  1. To do this, turn the ignition key switch OFF first.
  2. Then, disconnect connector G6 and connect connector G27 instead. G6 is the main throttle motor connector while G27 allows us to test the motor individually.
  3. Now we can check the throttle motor resistance.
  4. Use your multimeter probes to measure between pins G6-2 and G6-1 on the motor side.
  5. The standard readings we’re looking for are: 0.3 to 100 ohms at 20°C.
  6. We want the resistance reading to be somewhere between 0.3 and 100 ohms when the motor is at room temperature. If the reading is way outside this range, there’s likely an issue with the motor’s resistance internally. This could be due to worn-out windings or bad connections.
G6-2 ~ G6-10.3 ~ 100 Ω (20°C)
The throttle motor should show these resistance readings (Motor side).

When resistance is the culprit, there are a few ways you can get things back in shape:

  • Clean the motor connectors and pins to clear any corrosion or dirt buildup causing high resistance. Use electrical contact cleaner spray.
  • Test the motor windings for opens or shorts. If found, the motor will likely need replacement.
  • Check wiring between the motor and ECU for damage that could introduce resistance. Repair any cuts, fraying, etc.

The key is zeroing in on any resistance abnormalities and eliminating their cause.

2). Throttle Valve Drive Condition Inspection

If the throttle motor checks out okay, the next step is to take a look at the throttle valve. There are a couple of standard checks to perform to ensure the valve is working right:

1. The throttle valve should operate smoothly when fully opened. This means when you push the throttle down, it should move smoothly without catching or sticking. If it does not operate smoothly, it could indicate a mechanical issue like binding, contamination, or wear and tear.

2. The throttle valve should operate smoothly when fully closed. Similarly, when you let off the throttle and it returns to the closed position, it should move smoothly back to closure. Any sticking, catching, or uneven movement could signify a problem.

3. The throttle should return to opener angle when released. When you let go of the throttle, it should spring back to the idle/opener angle position. If it sticks part-way, doesn’t return at all, or goes past the opener angle, it suggests an issue with the return spring or mechanism.

Overall, the throttle valve needs to move through its full range of motion smoothly and precisely, both when actuated and when returning. Any deviation from the standard values indicates a potential issue needing diagnosis and repair. Binding, sticking, contamination in the mechanism, or spring and linkage wear could all contribute to abnormal operation.

3). Harness Continuity and Short-Circuiting Inspection

Once you’ve ruled out problems with the throttle motor and throttle valve drive on your Toyota forklift, it’s likely an electrical issue triggering the E06-1 and E06-2 error codes. The wiring harness, which relays power and signals through the forklift, may have continuity or short circuit problems.

Here’s how to inspect the harness for continuity and short-circuiting:

1. Turn the ignition key switch to the OFF position.

    2. Disconnect connectors G27 and G6.

    3. Then, use a multimeter to check for continuity between the following points:

    • G27-6 to G6-2: You should find continuity here.
    • G27-5 to G6-1: Continuity should also be present here.

    4. You should also ensure there is no continuity between these points:

    • G27-6 to the Frame
    • G27-5 to the Frame
    • G27-6 to G27-5
    • G27-6 to G27-7
    • G27-5 to G27-7
    G27-6 ~ G6-2Continuity
    G27-5 ~ G6-1Continuity
    G27-6 ~ FrameNo Continuity
    G27-5 ~ FrameNo Continuity
    G27-6 ~ G27-5No Continuity
    G27-6 ~ G27-7No Continuity
    G27-5 ~ G27-7No Continuity
    The table lists standard continuity and short circuit readings for harness inspections.

    If any of those readings are out of spec, there’s likely a wiring issue causing the E06-1 code. A break in continuity means there’s an open circuit, while unwanted continuity points to a short circuit. Make sure to thoroughly inspect the harness connectors and wires. Look for chafing, bare wires, corroded terminals, etc. Repair or replace any damaged wiring as needed.


    When you see the E06-1 and E06-2 error codes flashing on your Toyota forklift, it’s a sign that something’s up with the throttle system. These codes mean there could be issues with the throttle motor, wiring, or engine control unit. To fix it, you need to follow some steps. First, reset the error code. Then, check the water inlet connections. After that, test the throttle motor’s resistance and valve. Finally, inspect the wiring harness for any issues. By doing these steps, you can find out what’s wrong and get your forklift back to working well and safely.

    Toyota Forklift E02-1, E02-2 Troubleshooting Guide

    Error codes E02-1 and E02-2 can disrupt Toyota forklift operations and lead to frustration. This post sheds light on these error codes and provides you with a practical approach to resolving them. Explore the resetting guide, troubleshooting tips, and essential knowledge to solve error codes 02-1 and 02-2 in the Toyota forklift.

    Error Codes E02-1 and E02-2 on Toyota Forklift

    Error codes 02-1 and 02-2 on a Toyota Forklift indicate an abnormality in the intake temperature sensor. In simpler terms, this means that there is an issue with the sensor responsible for measuring the temperature of the air going into the forklift’s engine.

    When the intake temperature sensor malfunctions, it can have a noticeable impact on the Toyota forklift’s performance. The engine may experience difficulties in adjusting the air-to-fuel ratio, leading to suboptimal combustion and reduced power output. This can result in decreased acceleration, lower overall performance, and potentially even engine stalling or hesitation during operation.

    An illustration of the portion related to Toyota forklift error codes 02-1 and 02-2.

    Several factors can contribute to the occurrence of 02-1 and 02-2 error codes. The most common causes include a defective intake temperature sensor itself, a faulty wiring harness connecting the sensor, or a defect in the engine controller responsible for interpreting sensor signals. Identifying and addressing these underlying issues is essential for solving the E02-1 and E02-2 fault codes in the Toyota forklift.

    Probable Causes

    There are three main causes of the E02-1 and E02-2 error messages on the Toyota forklift.

    • Intake temperature sensor defect
    • Harness defect
    • Engine controller defect

    Resetting Guide

    To reset error codes 02-1 and 02-2 on a Toyota forklift, follow these steps:

    1. Disconnect the battery negative terminal and wait for more than 10 seconds.
    2. Inspect and correct any disconnection or water entry issues in connectors C3 and AC2.
    3. Reconnect all connectors, ensuring they are securely attached.
    4. Reconnect the battery negative terminal.
    5. Turn the ignition key switch to the ON position and start the engine.
    6. Check whether the error codes have cleared.

    If resetting successfully clears the error codes, it indicates a possible connector contact defect. To resolve this issue, thoroughly inspect the connectors, ensuring they are clean, free from corrosion, and making proper contact. Address any defects or connection issues, and then retest the forklift to ensure the error does not reappear.

    However, if the error codes persist even after resetting, further troubleshooting is required. In such cases, it is recommended to inspect the intake temperature sensor and its harness for any defects, such as physical damage or loose connections. Additionally, check for short circuit continuity in the sensor and harness. Detailed instructions for troubleshooting these components can be found below.

    Troubleshooting Guide

    Resolving error codes 02-1 and 02-2 on a Toyota forklift requires a systematic inspection of the following components:

    a). Intake Temperature Sensor Individual Inspection

    The intake temperature sensor plays a crucial role in the forklift’s operation. It measures the temperature of the air being drawn into the engine, providing important data to the engine controller for optimizing fuel-air mixture and combustion. Incorrect readings from this sensor can trigger error codes and adversely affect the forklift’s performance.

    To carry out the intake temperature sensor individual inspection, follow these steps:

    1). Ensure the ignition key switch is in the OFF position.

    2). Disconnect connector C3 and connect connector A35.

    3). Using a multimeter, measure the resistance between terminals C3-1 and C3-2.

    4). The readings should be approximately 2.45 ± 0.24 kilo-ohms at 20°C (room temperature) and 0.32 ± 0.03 kilo-ohms at 80°C (higher temperature).

    C3-1 ~ C3-22.45 ± 0.24 kΩ (20°C)
    0.32 ± 0.03 kΩ (80°C)

    5). By checking these resistance values, you can determine if the intake temperature sensor is functioning correctly. Any significant deviation from the specified readings may indicate a defect in the sensor, requiring further investigation and potential replacement.

    b). Harness Continuity and Short Circuit Inspection

    The harness connects various components, including the sensor, to the engine controller. Any issues with the harness can disrupt the flow of electrical signals and trigger error codes 02-1 and 02-2.

    To conduct the harness continuity and short circuit inspection, follow these steps:

    1). Ensure the ignition key switch is in the OFF position.

    2). Disconnect connectors A35 and C3.

    3). Measure the continuity between terminal A35-29 and C3-2. There should be continuity, indicating a proper connection.

    4). Measure the continuity between terminal A35-28 and C3-1. There should also be continuity between these terminals.

    5). Measure the continuity between terminal A35-29 and the frame of the forklift. There should be no continuity, indicating no direct connection to the frame.

    A35-29 ~ C3-2Continuity
    A35-28 ~ C3-1Continuity
    A35-29 ~ FrameNo continuity

    6). By performing these continuity tests, you can verify that the harness is properly connected and not experiencing any short circuits. If any continuity or short circuit issues are detected, further inspection and potential repairs or replacements may be necessary to rectify the problem.


    Error codes E02-1 and E02-2 indicate an issue with the intake temperature sensor of the Toyota forklift. These fault codes can arise from a defective sensor, a faulty wiring harness, or a malfunctioning engine controller. If resetting doesn’t clear the error, the troubleshooting includes inspecting the intake temperature sensor and its harness for defects and checking for short circuits. 

    Without resolving these errors, the engine may experience difficulties in adjusting the air-to-fuel ratio, leading to inefficient combustion. This can result in reduced power output, decreased acceleration, and overall lower performance of the forklift. In some cases, the engine may even stall or hesitate during operation, hindering productivity in a warehouse or industrial setting.

    Toyota Forklift Error Code E01-6 Troubleshooting Guide

    The Toyota Forklift error code 01-6 is an alert of something wrong with your Toyota Forklift.

    The E01-6 is either detected via the OBDII code reader or pops up in the forklift’s control panel display.

    This article here shares complete information on the E01-6 fault code on Toyota Forklift – what does it mean, how to reset it, and how to troubleshoot.

    Error Code E01-6 on Toyota Forklift

    Error Code E01-6 on a Toyota forklift indicates an O2 sensor heater open abnormality.

    The O2 sensor measures the oxygen content in the exhaust gases and provides feedback to the engine control unit (ECU). This information helps the ECU adjust the air-fuel mixture to optimize combustion efficiency. The heater is responsible for heating the O2 sensor to its operating temperature quickly, allowing it to generate a voltage signal.

    An illustration of the portion related to Toyota Forklift Error Code E01-6.

    An O2 sensor heater malfunction can have several effects on the forklift’s performance:

    • It can lead to inaccurate readings from the O2 sensor, causing the engine to run inefficiently. This can result in decreased fuel efficiency, reduced power, and increased emissions.
    • It may prevent the engine from entering closed-loop operation, where it relies on the sensor’s feedback for precise fuel control.

    A properly functioning O2 sensor and heater allow the engine control system to make accurate adjustments, leading to better fuel economy, performance, and reduced emissions. Ignoring or delaying the repair can result in decreased efficiency, increased fuel consumption, and potential damage to other engine components over time. Therefore, it is important to address the issue promptly and have it resolved by a qualified technician or service center.

    Probable Causes

    Toyota Forklift O2 sensor heater open abnormality can occur due to one of three reasons, triggering the E01-6 code.

    1. O2 sensor defect – refers to a failure of the oxygen sensor
    2. Harness defect – refers to a wiring issue, such as a loose or broken connection
    3. Engine controller defect – refers to a failure of the engine control module (ECM) or electronic control unit (ECU)

    Resetting Guide

    Resetting Toyota Forklift fault code E01-6 is a quick and easy fix to address an issue, but if it persists, it may indicate a faulty part or sensor that needs replacement.

    Here are the steps on how to reset the E01-6 error code on a Toyota forklift.

    1. Disconnect the negative battery terminal for 10 seconds.
    2. Inspect C1 and AC2. Check for any loose or broken connections, as well as signs of water entry or moisture damage.
    3. Reattach any disconnected connectors and then reconnect the battery’s negative terminal.
    4. Start the engine.
    5. This will reset the Toyota Forklift E01-6 error.

    Troubleshooting Guide

    In some cases, following the aforementioned reset instructions can resolve the error. However, if the error persists, it is necessary to proceed with troubleshooting to identify and address the underlying issue. Follow the inspection process in sequential order.

    1). O2 Sensor Individual Inspection

    Carry out an individual inspection of the O2 sensor. The O2 sensor is responsible for measuring the oxygen content in the exhaust gases, providing essential feedback for optimal fuel-air mixture regulation and emission control. A defective O2 sensor leads to poor fuel economy, increased emissions, and performance issues.

    To conduct the inspection, follow these steps:

    a). Turn off the ignition key switch.

    b). Disconnect connector C1.

    c). Connect connector A35.

    d). Take the O2 sensor readings.

    e). Ensure the following standard readings are within the specified range:

    C1-2 ~ C1-113 ~ 16 Ω (20°C)
    Resistance between terminals C1-2 and C1-1 should be between 13 to 16 Ω at a temperature of 20°C.

    A faulty O2 sensor can also trigger E01-5. Read more about Toyota Forklift error code E01-5 here.

    👉 If the error code is resolved, it’s good.
    Otherwise, move to the next inspection step below.

    2). O2 Sensor Heater Power Voltage Inspection

    Inspect the O2 sensor heater power voltage. The O2 sensor’s heater is responsible for reaching and maintaining the optimal operating temperature of the sensor. The heater ensures the proper functioning of the O2 sensor.

    To perform the inspection, follow these steps:

    a). Turn off the ignition key switch.

    b). Disconnect connector C1.

    c). Connect connector A35.

    d). Start the engine.

    e). Take voltage readings. The expected voltage readings should be between 8 to 16 V:

    C1-2 ~ Frame8 ~ 16 V

    A poor voltage power in the O2 sensor heater can also trigger E01-4. Read more about Toyota Forklift error code E01-4 here.

    👉 If the error code is resolved, it’s good.
    Otherwise, move to the next inspection step below.

    3). Harness Continuity and Short Circuit Inspection

    Inspect the harness for continuity and short circuits. Harness continuity refers to ensuring that there is a continuous flow of electrical current through the wiring harness without any breaks or interruptions. Short circuits, on the other hand, occur when there is an unintended connection between two wires or terminals, causing electrical current to flow where it shouldn’t.

    Inspecting the harness for continuity and short circuits ensures proper electrical connections and prevents issues such as electrical malfunctions, circuit failures, or potential damage to the forklift’s components.

    To perform the inspection, follow these steps:

    a). Turn off the ignition key switch.

    b). Disconnect connector A35.

    c). Disconnect connector C1.

    d). Check for continuity.

    e). Ensure there is continuity between A35-6 and C1-1, indicating a proper electrical connection. 

    f). At the same time, there should be no continuity between A35-6 and Frame, ensuring there are no unintended connections.

    A35-6 ~ C1-1Continuity
    A35-6 ~ FrameNo continuity

    Summary Points

    The Toyota Forklift error code E01-6 indicates an O2 sensor heater open abnormality.

    The O2 sensor measures the oxygen content in exhaust gases, providing feedback to the engine control unit (ECU) for optimal fuel-air mixture regulation.

    The error can be caused by a defective O2 sensor, a harness defect, or an engine controller defect.

    Resetting the error code involves disconnecting the negative battery terminal and inspecting connectors C1 and AC2 for loose connections or water damage.

    If the error persists, further troubleshooting is required. This includes individual inspections of the O2 sensor, checking the O2 sensor heater power voltage, and inspecting the harness for continuity and short circuits.

    Proper maintenance and timely resolution of the error are crucial to ensure optimal performance, fuel efficiency, and reduced emissions in the Toyota Forklift.

    Master Warning Light On Nissan – Causes & Fixes

    Out of all the warning lights you may see on your Nissan’s dashboard, the master warning light is usually not something to be desperate about. Firstly, it may not be a fault at all, but a condition, such as an open door. More importantly, the car will often display a supplemental message with the details of the error. In this article, we’ll take a look at the different variants of the Nissan master warning light, its causes, and the fixes of this orange triangle with an exclamation point in Nissan cars.

    Nissan Master Warning Light Symbol

    Nissan car owners will recognize the master warning light by its triangular shape, with an exclamation mark in the center. The master warning light should illuminate in combination with other lights that point to an issue on a specific system, or show up with an explanation message.

    Master Warning Light on Nissan Car

    There are several colors in which warning lights display on Nissan, with the most important ones being:

    • Red: These lights should get your attention and typically need to be addressed immediately: however, some of them don’t indicate a fault, but a condition, such as the parking brake is applied.
    • Yellow: Usually indicates faults on systems such as the ABS, parking brake, powertrain, or low tire pressure, among other conditions.
    • Other: A green, blue, or white symbol light indicates that a given system is on (for example, high beam assist or fog lights).

    The master warning light usually shows up in a red or yellow triangle with an exclamation point in Nissan cars. The cause and meaning of the warning light vary based on its color. The causes will vary from model to model and on different generations; consult your owner’s manual for info specific to your model.

    Causes For The Master Warning Light On Nissan – Red

    An image of a yellow-colored triangle with an exclamation mark, known as the Master Warning Light, illuminated on a Nissan Rogue due to an engine malfunction.

    A red master warning light on Nissan may indicate some of the following:

    • An engaged parking brake
    • A warning from the transmission system
    • Steering wheel hands-on detection warning
    • An open door
    • On some electric Nissan cars, in case of a DC/DC converter issue, together with the battery warning light

    The following steps may help with the listed issues:

    • Check whether the parking brake is engaged. Release the parking brake before driving. If the light is on while the parking brake is disengaged, check for issues with the parking brake.
    • Check the current position of the shifter. If the car is parked, engage the parking brake. Check for issues in the transmission system.
    • Don’t take your hands off the steering wheel while driving! If the Steering Assist is faulty, it should automatically turn off. If there’s a fault with the steering assistance or any of its functions, have your car checked.
    • Latch all doors before driving.
    • Don’t drive if there is a battery warning while the car is running – it means that your battery is discharging. Have your car checked by a qualified electrician.

    Causes For The Master Warning Light On Nissan – Yellow

    Yellow triangle master warning light is illuminated on the Nissan Qashqai Tekna, indicating the need for servicing of the e-power system.

    While yellow warning lights typically aren’t as alarming as red ones, they shouldn’t be ignored. Possible causes include:

    • A low fuel level
    • No keys detected
    • Low windshield washer fluid level
    • A loose fuel cap
    • Low tire pressure
    • Open trunk
    • An open door (when stopped)
    • 4WD error, on models that have 4WD

    The troubleshooting for most of these causes is simple:

    • Top up fuel levels.
    • Make sure the keys are not too far away from the car. If the car still doesn’t detect the keys, there may be an issue with the key or within the car.
    • Top up windshield washer fluid.
    • Screw the fuel cap on correctly after refueling.
    • Inflate the tires up to the recommended pressure.
    • Latch the trunk and all the doors before driving.
    • The 4WD has many components which could be at fault, from any of the sensors to the control unit– consult a trusted repair shop.

    Meaning of Exclamation Point Inside of a Triangle In Different Nissan Vehicles

    The red or yellow triangle with an exclamation point serves as a common indicator across all Nissan vehicles.

    Here are some likely causes you should watch out for in various Nissan models:

    Nissan Altima

    A loose fuel cap is a common cause of this occurrence. Another common reason is leaving the headlights on when exiting the vehicle. Make sure the headlights are off after leaving the vehicle, as they can drain the battery over time.

    Nissan Rogue

    The master warning light in Nissan Rogue is typically triggered by two main issues: power steering problems and overheating within the AWD system.

    Nissan Qashqai

    The triangle malfunction light in Nissan Qashqai usually indicates that the fuel level is nearing empty. Also, a convenient feature of the Qashqai is that it accompanies the triangle symbol in conjunction with an error message in the message center, providing clear and concise information about the issue at hand.

    Nissan Sentra

    The warning malfunction indicator light commonly activates when Sentra is low on gas or has a missing or improperly tightened fuel cap.

    Nissan Pathfinder

    The exclamation point inside of a triangle in Nissan Pathfinder usually means there is an overheated all-wheel drive system.

    A picture depicting the Master Warning Light illuminated inside a Nissan vehicle that was recently brought to my workshop for inspection. The reason behind the warning light being activated is attributed to issues within both the engine (see the check engine light on the tachometer) and the Forward Emergency Braking system (see the Forward Collision Warning Light on the speedometer).

    Nissan Murano

    The triangle warning dashboard light serves as a broad indicator that something requires attention or troubleshooting in the Murano.

    Nissan Kicks

    The blinking master warning light indicates an emissions control malfunction. This means a problem or issue with the components responsible for managing and reducing harmful exhaust emissions in the Nissan Kicks.

    Nissan Maxima

    The exclamation point symbol typically indicates low tire pressure.

    Nissan 370z

    Nissan 370Z is a sporty and performance-oriented car model known for its power and handling capabilities.

    In Nissan 370Z, the master warning light illuminates due to:

    ➜ No key warning: Indicates that the key is not detected or is not within the range for starting the vehicle.

    ➜ Low fuel warning: Alerts the driver that the fuel level is running low and requires refueling.

    ➜ Low washer fluid warning: This indicates that the windshield washer fluid level is low and needs to be replenished.

    ➜ Parking brake release warning: Reminds the driver to release the parking brake before driving.

    ➜ Door/rear hatch open warning: Notifies the driver if any of the doors or the rear hatch is open, ensuring they are closed properly for safe operation.


    What To Do When The Master Warning Light Comes On In Your Nissan Vehicle?

    Your course of action depends on the cause. After checking all the essentials, such as the doors and the trunk, and making sure there is enough fuel, the warning should be gone, and you can drive on as usual.

    However, if the warning shows up with another error light that indicates a deeper issue, it’s best to get your car diagnosed and repaired by a professional. Some issues, like a burst tire, may make it unsafe to keep driving; in that case, stop at a safe place as soon as you can.

    How to Perform A Nissan Master Warning Light Reset?

    The Nissan master warning light should never be manually reset without prior diagnostics. It’s because it is designed to alert the driver to potential issues with their vehicle.

    If the error causing the warning light is not resolved and you manually reset the light, it will temporarily turn off but will activate again once the engine detects the same issue.

    To reset the Nissan master warning light, you can use any compatible diagnostic software; for a simple reset, a simpler, universal tool should also work. Only erase DTCs after the issue has been resolved.

    If you decide to reset the car by disconnecting the battery terminal, keep in mind that this may also undo your clock settings, and infotainment system settings, and, in older vehicles, it may reset the fuel trip as well. Therefore, be prepared to reconfigure these settings after the reset.

    Can the Master Warning Light Reset Itself?

    Typically, the master warning light will automatically reset only when the underlying issue that triggered the light has been resolved.

    However, sometimes a “history” DTC will be left after the underlying cause is resolved. These DTCs indicate a fault that is not present at the moment, and once erased, the light will go off.


    There isn’t one definitive reason the master warning light illuminates in Nissan cars. And this triangle with an exclamation point inside is usually accompanied by further warning lights and/or display info. The two variants, red and yellow, differ in meaning and severity. The causes for the triangle light range from something as simple as a loose fuel cap to more complex issues that require a professional inspection.

    How To Reset MPG On Toyota Highlander?

    Many modern cars, including the Toyota Highlander, have the convenient option of showing fuel economy information, like the MPG and distance to E, on the dashboard. Consequently, resetting the MPG takes a few simple steps.

    The procedure may vary slightly between different manufacture years, but in general, there are two types of reset: with the “OK” button and the gauge cluster button.

    Resetting The MPG On Toyota Highlander

    ✅ To reset the MPG on the Toyota Highlander, scroll using the up and down arrows on the steering wheel, and hold the “OK” button. The fuel economy value will then be measured from the reset onward. Ta-da!

    ✅ However, if your Highlander has instrument cluster buttons, follow these steps:

    1. Press and hold the reset knob on the bottom right side of your dashboard to open the settings menu.
    2. Once the menu is on your dashboard display, rotate the knob until the “Fuel reset” is highlighted.
    3. Make sure the chosen reset method is “Manually”.
    4. Press “Back” to return to the menu.
    5. Scroll to “Default” in the dashboard menu and press the knob to reset.
    6. Choose “Back” to exit the menu.

    The fuel economy value should now be reset!

    ✅ If you have a new Toyota Highlander model, like the third-generation XU50 or fourth-generation XU70, you can reset the vehicle’s MPG via the Toyota App installed on the infotainment system.

    To begin, simply navigate to the Toyota App ➜ Vehicle ➜ Trip Information ➜ History and then click Update. This will store your current MPG reading in the vehicle’s history, and start a new total measure of the fuel efficiency. You can also click the “Clear Data” option.

    By selecting this option, the total MPG reading will be reset to zero, and the history of previous readings will also be cleared.

    The Actual Gas Mileage On Your Toyota Highlander May Vary

    Since the fuel economy values can be reset, and likely have been at some point, it may not reflect your current consumption. However, statistically, the further you drive, the more accurate the estimate gets.

    On some newer Highland models, you’ll be able to see the current fuel economy on the dashboard, since the consumption can change rapidly in different driving conditions. For example, city driving usually tends to consume more than driving on a highway, because of slower speed and higher RPM.

    Knowing that the consumption is only an estimate, the remaining distance, or “Distance to Empty” should also be taken with a grain of salt. The remaining distance is calculated based on your average consumption, therefore, if you’re in driving conditions that demand more fuel, you won’t be able to go as far as your display states.

    In some cases, the remaining driving distance may not change if you added a small amount of fuel. If it’s displaying “Refuel”, that means your fuel levels are critically low, and the remaining distance cannot be calculated.

    Brake Override Malfunction: What It Is, How To Solve (The Complete Guide)

    The “Brake Override Malfunction” is a rare issue that can occur in your vehicle, but it is easily manageable and can be resolved without causing any inconvenience or danger.

    When this error appears on your car’s dashboard, it may catch your attention, but with proper guidance, it can be fixed quickly, allowing you to continue with your daily routine without any disruption, whether it’s leaving for work in the morning or embarking on a trip.

    The symptoms associated with this issue are minor and can be quickly resolved with the help of a diagnostic software tool.

    Despite its intimidating name, brake override malfunction is not a major issue, and there are only a few reasons why it may occur, most of which are relatively easy to fix and don’t require any expensive parts.

    In this article, we’ll delve into the various causes of this issue and provide simple solutions to each one.

    What Does The Brake Override Malfunction Mean?

    Brake Override Malfunction
    A Brake Override Malfunction error is displayed on a car’s dash.

    A brake override malfunction occurs in a vehicle’s electronic control system, where the software that controls the brakes and accelerator becomes confused and fails to respond to the driver’s acceleration input.

    In most cases where you see this error, there actually is a fault that’s causing the car to think that someone’s tampering with the gas and brake pedals. Some very common causes for this include a blown fuse or a broken brake pedal switch, though there are more subtle ones.

    The Brake Override Malfunction is also called the “Brake and Race Pedal” error because it is sometimes identified by the brake and race pedal symbols on the dashboard of the vehicle.

    How Does Brake Overriding Work?

    Your brake override system is in place to protect you from improper pedal use and prevent potential malfunctions and accidents caused by it.

    If you, for whatever reason, voluntarily or involuntarily press the brake and the acceleration pedals at the same time (maybe in a frantic attempt to slow down the car,) the sensors will notice unusual behavior and put brake override into effect.

    The brake override tries to clear the confusion by doing the thing that’s usually safer: instead of uncontrollably speeding up, it will slow the car down. It’s worth noting you can turn the brake override off, but it’s not recommended to do this if you haven’t fixed the underlying cause!

    What Causes The Brake Override Error + How To Fix

    Here are some of the most common causes that may give you a hint of what to check if you have this error:

    A Blown Brake System Fuse

    This is an extremely common issue, and thankfully, it’s also easy to solve. A fuse blows when there is a current overload in a circuit, protecting the components from damage and/or fire. The fuse can blow as a one-time event if an unusual event happens, but if it keeps happening, it’s likely there’s an underlying electrical issue.

    You can usually find fuses in fuseboxes near or under the steering wheel, around the glovebox, under the hood, next to the battery, and/or in the rear. Check the fuses using a probe, and always replace them only with a working fuse of the same marking, never higher!

    A Faulty Brake Pedal Switch

    Another one of the more frequent causes is a faulty brake pedal switch (or the brake pedal positions sensor), which can trick your car into thinking the brake pedal is depressed when it is not. This piece of electronics is usually a simple microswitch that activates once you press the brake pedal and lets the car know you’re acting on the brake pedal.

    In this case, you should check the wiring leading to the sensor and replace the switch if there seems to be a problem with it. The sensor is usually located under the dash, near the pedal itself.

    A Faulty Airbag Module

    You might be confused at first, thinking, what does the airbag module have to do with the brakes? It’s simple: the brake system and the airbag system both have a safety role, and they communicate with each other.

    So, if a fault occurs in your brakes and leads to a brake override, the airbag may shut down too. You may notice this in the form of an airbag warning light and on newer cars a warning message in addition to the light.

    Before replacing the module, make sure that it’s not a sensor or the wiring that’s causing the issue. It’s also best not to tamper with the airbag unless you’re a professional, as accidentally triggering an airbag not only damages the car but can also cause severe injuries. Even worse, you don’t want the airbags to not deploy in the case of a crash!

    Issues With The ABS Module

    The ABS module is the main control unit for the brakes, and if it fails, it’s possible you’ll get a brake override warning. While this is less common than a brake switch fail or a blown fuse, it can still happen, even in newer cars.

    Replacing the ABS control unit can be costly, depending on the vehicle, so do check with your local service about the price.

    Other Issues

    There is a multitude of other potential issues that can cause a brake override error. Worth mentioning are: 

    • Corroded, broken, or incorrect wiring
    • Tameping with the braking or any related system
    • Replacing brake lights or rewiring them incorrectly
    • A weak battery in the key fob

    You can only get a more precise clue about the issue after checking with a diagnostic tool. It’s time-consuming and unnecessarily painful to try to blindly guess what’s the issue. If it’s more than just a blown fuse and you don’t have the appropriate tools, it’s best to send your car to a car shop.

    Brake Override Malfunction Error Resetting Guide

    Blinking Brake Override Malfunction error message.

    If you encounter a brake override malfunction error on your car, there is a universal temporary solution that may help you get back on the road until you can take your vehicle to a mechanic. It’s important to note that while this method should work on most vehicles, there may be different methods for different cars.

    Here are the steps you can take to reset the brake override malfunction error:

    1. Disconnect the battery terminals, starting with the negative terminal first and then the positive.
    2. Connect the two cables to each other and hold them in place for 15 minutes. This will not affect anything in the car since the battery power has not been connected.
    3. With the cables still connected, turn the headlights knob in your car to full. This will drain all the electrical power from your car, which will reset all of its electronic systems.
    4. After 15 minutes, plug the cables back into the battery, starting with the positive first and then the negative.
    5. Once the battery terminals are well connected, start your car and the brake override malfunction error should be gone.

    Keep in mind that this is only a temporary or emergency solution, and you should take your car to a mechanic as soon as possible. Additionally, this may not be a permanent fix, so it’s best to get your car checked out by a professional.

    Can You Drive With Brake Override Malfunction?

    In some cases, you’ll still be able to control the car, while in others you might not be able to change gears and drive at all. In either case, a brake override malfunction is a failure of a crucial safety system of your car, so it’s best to get it checked and fixed as soon as possible.

    For a short period of time, you can ignore the brake override issue and turn the system off. The procedure for this differs from car to car, so you’ll have to find the exact procedure in the owner’s manual. You should only do this so that you can get your car to the repairer.


    A brake override malfunction is a safety issue, but it’s usually not a difficult fix. The telltale sign is a dashboard warning, while other symptoms can include a malfunctioning gearbox, airbag, and brake system.

    If the fuses and the key fob battery are ok, there’s not much you can do without professional equipment, and you should get your car checked since driving with a brake issue can be dangerous.

    How To Turn Off Master Triangle Warning Light On Toyota Highlander

    Many cars have something similar to the master warning icon present on Toyota models, including the Highlander. It usually looks like a yellow or orange triangle with an exclamation mark in the center.

    The master warning light can have many meanings, from an open door to a maintenance reminder to a fault in your powertrain, and it usually lights up in combination with other warning lights. Those other lights can point in the direction of the underlying issue, such as the engine. Turning off the master warning light means targeting the underlying issues.

    What do the different combinations of sound and flashing that come on with your master warning light mean? How can you turn it off? What steps should you take if you see this warning on your Highlander? We’ll answer all these questions and more in the following article.

    What Does The Triangle Master Warning Light On Toyota Highlander Mean?

    To figure out what the master warning icon means on your Toyota Highlander, you’ll have to see what exactly it’s signaling. The 2019 Toyota Highlander owner’s manual explains the warning light:

    “A buzzer sounds and the warning light comes on and flashes to indicate that the master warning system has detected a malfunction.”

    The buzzer and the warning light, in turn, are also accompanied by a warning message on the multi-information display, where you should see more info about the exact issue.

    Toyota Highlander Triangle Master Warning Light
    The Master Warning Light on Toyota Highlander looks like a yellow or orange triangle with an exclamation mark in the center. It is accompanied by a warning message on the multi-information display.

    The master warning system incorporates pretty much everything that may present a problem while driving, even if it’s not a fault on your car. The seriousness of the issue can vary as well. While some issues can be fixed on the spot, others will require either an immediate or a non-urgent inspection.

    How Do I Turn The Master Warning Light Off On Toyota Highlander?

    To turn off the master warning light on your Toyota Highlander, it’s important to diagnose the underlying issue. Or simply cleaning the DTC or resetting the service due.

    To identify the cause of the warning light, you can use the steering wheel controls to cycle to the error in the alerts/warnings section of the menu bar. From there, you can scroll down to view the specific issue. If there are no alerts or warnings, then everything is likely fine and you can proceed to reset the warning light.

    The blinking triangle exclamation mark on Toyota Highlander’s dashboard is a Master Warning Light.

    Here’s how to reset the master warning light on a Toyota Highlander:

    1. Press the return key on the steering wheel.
    2. Press the menu key.
    3. Use the side arrow key to navigate to the ‘wheel’ icon on the screen.
    4. Scroll down the wheel icon category until you find the ‘scheduled maintenance’ option.
    5. Press enter.
    6. A pop-up will appear asking whether to reset data, choose ‘Yes’.
    7. Your maintenance light will be reset, and the orange/yellow triangle exclamation mark will turn off.

    Causes And Fixes

    If the master warning light is illuminated and toggling over it displays alerts or warnings, then immediate attention is required. The cause of the warning could be as minor as an open door, an unbuckled seatbelt, irregular tire pressure, or even low windshield washer fluid. However, in certain Toyota Highland models, the master warning light may also be accompanied by other dashboard lights, particularly if the issue is more severe, such as an EPS or braking malfunction.

    The possible causes of the master warning light turning on in the Toyota Highlander are explained below:

    1. Door, Hood, Back Door, Or Glass Hatch Open

    Maybe it’s simply the case that you didn’t properly latch any of the doors or the hood. The warning pops up once your vehicle reaches a speed of above 3 mph, as the car assumes you started driving.

    Check if everything has clicked and if the doors aren’t sticking out. Perhaps there is an obstacle such as leaves or dust, so ensure all the latches are clean. If that does not help, it may mean there is a mechanical or electrical issue with the door latch.

    2. Inaccurate Tire Pressure

    Irregular tire pressure is a common cause of the master warning light coming on, especially in colder climates.

    Extremely high temperatures can lead to a significant increase in tire pressure, while extremely low ones have the opposite effect. Incorrect tire pressure can lead to lower fuel efficiency, reduced handling, and increased wear on the tires.

    To prevent this from happening, it is important to check your tire pressure regularly and ensure that it is at the recommended level. In the case of a Toyota Highlander, the recommended tire pressure is 36 psi for both the front and rear tires. This ensures that the tires provide optimal performance and durability, while also ensuring a safe and comfortable ride.

    3. An Issue In The EPS (Electric Power Steering)

    The EPS makes the steering wheel less heavy by measuring how much you turn the steering wheel and sending the appropriate amount of force to the wheels. It’s logical that when the EPS fails, steering will become more difficult.

    In this case, you will also see an EPS warning on the dash, which looks like a steering wheel with an exclamation mark right off it. You should get your car checked and fixed.

    4. Radar, Blind Spot Monitor, Or Park Assist Issue

    The warning for the radar cruise control may be due to bad weather, or because there is dirt obstructing the sensor. In the second case, you’ll have to clean the sensor and everything should start working normally.

    The Blind Spot Monitor (BSM) and the Park Assist can also report an error and stop working if they are covered with ice, mud, snow, etc. If this does not help, there may be an underlying issue, like a misaligned BSM sensor or any type of fault with the intuitive parking sensors.

    5. Abnormal Engine Oil Pressure

    If the engine oil pressure is too low, the multi-information display will tell you to stop your vehicle in a safe place.

    There are plenty of reasons for low engine oil pressure, such as low levels of oil, a wrong choice of oil, or an oil pump failure. Continuing your ride when this warning shows up means there’s a chance you’ll do great damage to your engine. Therefore, you should stop safely and get the car serviced.

    6. Braking Malfunction

    A malfunction in the car’s brakes, whether mechanical, hydraulic, electric, or electronic, can trigger the master warning icon and buzzer. Driving with this error can be dangerous, so you need to fix it as soon as you can.

    In this case, you’ll see a brake warning light beside the master icon. Causes for a brake issue can vary, but you most likely won’t be able to fix any without equipment, parts, and knowledge of the brake system.

    7. Maintenance Due

    Every couple thousand miles, your Highlander will remind you to perform routine maintenance. While this is not urgent, you shouldn’t wait forever before performing maintenance or having it done at a service.

    After finishing the maintenance, the warning won’t go away on its own. You’ll have to reset it, which can be done using the trip meter button in the following manner:

    1. Turn the engine switch to off/lock with the trip meter A shown (depending on whether you have a smart key or not).
    2. While holding down the trip reset button, switch to ON, but don’t start the engine.
    3. Hold the button until you see the trip meter displaying zeros.

    You can also reset the maintenance due using the multi-information display:

    1. With the engine on, press the gear icon.
    2. Select “Maintenance System”
    3. Select “Yes”
    4. The display should show “Initialization Completed.”

    This is the procedure for a 2019 Toyota Highlander model, and the exact steps may be slightly different in an older or newer Highlander. You can find the manual for your manufacturing year on Toyota’s website.

    What To Do If The Toyota Highlander Triangle Warning Light Turns On?

    Depending on the cause of your master warning light, these are the steps you should take:

    • If the cause is not a fault, in other words just a warning, take the appropriate action. Check that all doors, the hood, the back door, the glass hatch, and the moon roof are closed and whether something prevents them from closing fully. Also, disengage the parking brake before driving.
    • There are some fixes you can perform yourself. If the car reports a dirty sensor, clean it from any ice, snow, or mud. If the maintenance has been performed, but not reset, initiate the reset.
    • If there is an underlying fault, you will need to send your car to the dealership. Some faults don’t require immediate assistance but still have to be checked, while others, such as issues with the brakes or engine oil, need to be addressed as soon as possible.

    Assessing The Troubleshooting Urgency

    When the Toyota Highlander’s master warning light illuminates in a flashing or non-flashing state accompanied by an audible alert, it signifies an urgent problem that requires immediate attention. This could be a malfunctioning driving system, such as the brake system. Or a potential danger that may arise if the corrective procedure is not promptly performed.

    On the other hand, when the triangle with exclamation illuminates in a flashing or non-flashing state without an audible alert, it could indicate a possible malfunction in the electrical components or the need for routine vehicle maintenance. For instance, a dirty sensor, a malfunctioning airbag system, or the necessity of tuning for optimal performance.


    The triangle master warning light itself is vague, but it usually shows up with a message that explains the issue, and sometimes another warning, such as a “check engine” or brake warning.

    If there are no obvious driving hazards like an unlatched door or driving with the parking brake applied, the light may also show up because of maintenance due, to a dirty park assist or BSM sensor, or problems on the engine, brakes, or power steering.

    Some of these causes can be easily solved yourself, but if there is a more serious issue, it’s best to see a Toyota car service or dealership.

    Toyota Forklift Error Code E01-5: How To Clear This Fault Code?

    Toyota Forklift has a diagnostic system that can detect issues such as error code E01-5. This article discusses the E01-5 forklift fault code in detail, its resetting guide, and how to troubleshoot it.

    Understanding this error code and its diagnosis will help keep the forklift running smoothly.

    Error Code E01-5 on Toyota Forklift

    Error Code E01-5 on Toyota Forklift indicates an O2 sensor open abnormality. This means that the oxygen sensor is not receiving the return signal from the computer, which can be caused by a harness defect (broken wire or dirty connectors), a failed O2 sensor, or a defective ECM.

    When this error occurs, the engine speed can become unstable or it may even stop. This can limit the speed of traveling and materials handling due to limited engine power output.

    An illustration of the portion related to Toyota Forklift Error Code E01-5.

    It is therefore important to ensure that the O2 sensor functions properly, to maintain the performance of the engine and keep its operator safe.

    Probable Causes

    There are 3 main possible causes of the E01-5 error message on the Toyota Forklift:

    1. O2 Sensor defect 
    2. Harness defect 
    3. Engine controller defect

    Resetting Guide

    Resetting fault code E01-5 can often clear the issue. But if the error persists, it may indicate a faulty part or sensor that needs to be replaced. Here are the steps to reset the error code E01-5 on a Toyota Forklift:

    1. Disconnect the negative terminal of the battery for more than 10 seconds.
    2. Check the connection status of the C1 connector.
    3. Disconnect C1 and perform a visual and contact pressure inspection of the connector.
    4. Short circuit the service connector TC terminal with the E1 terminal.
    5. Connect C1 and the battery negative terminal. Note: For combination vehicles, switch the fuel changeover switch to gasoline.
    6. Turn the ignition key switch ON (engine stopped).
    7. Depress the accelerator pedal 5 times fully (from fully open to fully closed) within 30 seconds.
    8. Start the engine and check that the error has been cleared.
    9. Disconnect the battery negative terminal again.
    10. Disconnect the TC and E1 terminals.
    11. Reconnect the battery negative terminal.
    12. Start the engine and let it idle for a few minutes.
    13. Fully depress the accelerator pedal for 3 minutes with the direction neutral. Then release and leave the accelerator pedal.
    14. Run the engine at idle for 2 minutes.
    15. Repeat steps (13) and (14) for 3 times.
    16. Turn the ignition key switch OFF and leave it off for one minute.
    17. Repeat steps (12 to 16) for 3 times.
    18. This will clear the E01-5 fault code.

    Troubleshooting Guide

    Resetting the E01-5 error code on your Toyota Forklift is often the solution to the issue. In case resetting this code does not work, troubleshooting the issue can resolve the problem. To troubleshoot the problem, you should follow the inspection process in sequential order.

    1). Connector Contact Inspection

    The connector is a crucial component in a forklift’s electrical system that helps to establish a reliable connection between different parts of the system. It plays a critical role in ensuring that the various electrical signals are transmitted accurately and consistently, which is essential for the proper functioning of the forklift.

    A defective Connector contact could result in triggering the e015-error code on Toyota Forklift. Its fix typically involves replacing the damaged component with a new one.

    👉 If the error code is resolved, it’s good.
    Otherwise, move to the next inspection step below.

    2). Harness Continuity and Short Circuit Inspection

    The harness continuity refers to the uninterrupted flow of electrical signals through the wiring harness of the forklift. To ensure proper forklift performance, it’s important to address any breakage or damage in the harness, which could result in issues such as the e01-5 error code.

    To inspect for continuity and short-circuiting of the harness, it is necessary to turn off the ignition key switch and disconnect the A35 and C1 connectors. This will allow for a thorough inspection of the wiring harness.

    Standard readings are:

    A35-20 ~ C1-3Continuity
    A35-21 ~ C1-4Continuity
    A35-20 ~ FrameNo Continuity

    The fix would be to repair or replace the damaged harness to ensure the uninterrupted flow of electrical signals.

    👉 If the error code is resolved, it’s good.
    Otherwise, move to the next inspection step below.

    3). O2 Sensor Inspection for Connector Contact Defect

    The O2 sensor voltage inspection is a diagnostic procedure used to determine if the oxygen (O2) sensor in a Toyota forklift is functioning correctly.

    The O2 sensor measures the amount of oxygen in the exhaust gas to help the engine control system adjust the air/fuel mixture for optimal combustion.

    The connector connection plays a crucial role in transmitting the voltage signal from the O2 sensor to the engine control module. A faulty connector can cause voltage signal interference, leading to the engine control system receiving incorrect readings.

    1. To inspect the O2 sensor voltage output, start by connecting A35 and C1. 
    2. Then, start the engine and let it warm up completely. 
    3. Set the direction to neutral and fully press the accelerator pedal. 
    4. Measure the O2 sensor voltage using the I/O monitor: OX. 
    5. The Standard Voltage Readings should be: OX 0.4 V or less and 0.5 V or more alternately output. 
    6. If the readings are outside of this range, then there may be a problem with the connectors that connect the O2 sensor to the ECM.

    👉 If the error code is resolved, it’s good.
    Otherwise, move to the next inspection step below.

    4). O2 Sensor Voltage Inspection for Engine Controller Defect

    If the connector contact is functioning properly, you can assess any defects in the engine controller by taking O2 sensor voltage readings.

    In the case of a Toyota forklift, an engine controller defect may trigger an error code, as it regulates the air-fuel mixture and monitors the O2 sensor’s output.

    An engine controller defect can cause the check engine light to appear, and E01-5 or E01-1 or E01-2 codes to be generated due to incorrect voltage levels in the O2 sensor readings.

    To inspect the output of an O2 sensor in a Toyota forklift for checking engine controller defect, you can follow these steps:

    1. Disconnect the C1 connector.
    2. Connect a voltmeter or an oscilloscope probe to pin A35 of the connector.
    3. Start the engine and let it warm up completely.
    4. Set the direction of the forklift in neutral.
    5. Fully open the accelerator pedal.
    6. Read the O2 sensor voltage on the voltmeter or oscilloscope.
    7. The standard voltage readings should be OX 0.2 V or less (I/O monitor: OX).


    The Toyota Forklift’s E01-5 error code provides valuable information about the specific issue affecting the O2 sensor. By identifying an open abnormality in the sensor, the error code helps diagnose potential problems such as a faulty harness due to dirty connectors or broken wires, a malfunctioning O2 sensor, or a flawed ECM. This allows for targeted and effective troubleshooting to restore the forklift’s optimal functioning. While resetting the fault code may sometimes fix the problem, persistent occurrences may indicate the need to replace a defective part or sensor.

    To identify the issue, the article recommends examining the connector contact, testing the harness for continuity and short-circuits, and inspecting the O2 sensor for connector contact issues. To ensure optimal performance, it is recommended to check the engine controller if the issue persists.

    Auto wizardry for the modern driver!