Tag Archives: Troubleshooting

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 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 Codes E01-1, E01-2, E01-3, E01-4: How To Clear These Fault Codes?

As a Toyota forklift operator or mechanic, you know that occasional errors are a natural part of the job. It’s worth noting that E01-1, E01-2, E01-3, and E01-4 are common errors that you might encounter, but they’re not insurmountable challenges. These Toyota forklift error codes can be a headache, but fortunately, with a little troubleshooting, you can have your Toyota forklift up and running in no time.

Fortunately, in this guide, we’ll examine these errors in detail, clarify their meanings, and provide guidance on how to reset them.

So, whether you’re a forklift operator or a mechanic who’s eager to master the troubleshooting process of E01-1, E01-2, E01-3, and E01-4 errors on Toyota forklifts, keep reading!

Errors E01-1, E01-2, E01-3, E01-4 on Toyota Forklift

The Toyota forklift’s E01-1, E01-2, E01-3, and E01-4 codes suggest issues with the fuel delivery system or Fuel Feedback Control Abnormalities, but they’re not problems without solutions. If the forklift is consuming rich gasoline, it could trigger E01-1, whereas using lean gasoline could result in E01-2. On the other hand, Toyota forklifts running on rich or lean LPG can experience E01-3 and E01-4, respectively.

Toyota Forklift Error Codes E01-1, 01-2, 01-3, 01-4
An illustration of the portion related to Toyota Forklift Error Codes E01-1, 01-2, 01-3, 01-4

When the fuel feedback control system malfunctions, the engine may receive inaccurate information about the amount of fuel necessary to maintain a steady speed, leading to errors. This causes the Toyota forklift’s engine to stall or run erratically.

If you encounter these E01-1 to E01-4 error codes, it’s important to take action quickly to prevent further damage to your forklift and ensure that it’s safe to operate.

Probable Causes

Toyota forklift error codes E01-1, 01-2, 01-3, and E01-4 indicate one or more of the following different malfunctions.

  • Intake System Defect
  • Exhaust System Defect
  • Sensor Defect
  • Ignition Defect
  • Fuel System Defect
  • Harness Defect
  • Engine Controller Defect

Resetting Guide

Fortunately, resetting these codes can solve the issue. However, if the problem persists, it might indicate a faulty part or sensor that requires replacement. Here are the simple steps to reset error codes E01-1, E01-2, E01-3, or E01-4 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 reset the E01-1 or E01-2 on the Toyota Forklift.

Troubleshooting Guide

If for some reason the error code does not resolve by resetting it, don’t worry. You can move on to a more detailed troubleshooting process. This process involves inspecting different sensors and parts of the forklift to identify the root cause of the issue.

It is important to note that the inspection steps need to be followed in an accurate sequence to ensure that you do not miss any potential issues. Therefore, it is recommended that you start inspecting your Toyota forklift in the following sequence:

1). Air Intake Inspection

The method of troubleshooting starts with an air intake inspection. Simply start the forklift’s engine and check if there’s a presence of air being sucked in from the engine oil level gauge, oil filler cap, or PCV hose. As well as the connections between the air cleaner and the cylinder head.

Remember, there must be no air being sucked in as this can cause an imbalance in the air-fuel ratio, leading to an incorrect fuel feedback control. This can cause your Toyota forklift’s engine to misfire and result in the e01 error codes being triggered.

If air is being sucked into the system, the next step is to identify the source of the problem and make the necessary repairs. This may involve replacing damaged or worn components, such as hoses, seals, or gaskets, or cleaning or replacing the air filter.

👉 If the error code is resolved, good.
Otherwise, proceed to the next inspection step below.

2). Exhaust Gas Leakage Inspection

The Exhaust Gas Leakage Inspection is a diagnostic process that involves starting the engine and checking if there is any exhaust gas leakage from the exhaust system parts and connections between the cylinder head and the catalytic muffler.

Exhaust gas leaks can be prevented with proper maintenance and can help ensure optimal engine performance, improved fuel efficiency, and reduced emissions. In addition, taking steps to prevent exhaust leaks can also help protect the health and safety of operators and other personnel who may be exposed to toxic fumes.

👉 If the error code is resolved, good.
Otherwise, proceed to the next inspection step below.

3). Fuel Leakage Inspection

Regular maintenance can help prevent fuel leakage in forklifts and promote increased fuel efficiency, reliable engine performance, and decreased environmental pollution. Moreover, ensuring proper fuel system maintenance can help prevent workplace accidents and minimize the risk of fire hazards.

To troubleshoot Toyota Forklift errors between E01-1 and E01-4, the first step is to start the engine and visually inspect the fuel system parts and connections between the fuel pump and injectors for any signs of fuel leakage. If fuel is detected, it’s important to identify the source of the problem and fix it immediately to prevent further damage or safety risks.

👉 If the error code is resolved, good.
Otherwise, proceed to the next inspection step below.

4). Fuel Pressure Inspection (for Gasoline) / Regulator Primary Pressure Inspection (for LPG)

Toyota Forklift error codes E01-1 and E01-2 can be useful indicators of potential fuel system issues. By identifying and addressing problems with components such as the pressure regulator, fuel filter, or fuel pump, forklift operators can help ensure optimal performance and efficiency.

Fixing pressure regulator defects can help promote proper fuel pressure and prevent performance issues while resolving fuel filter defects can help prevent blockages and maintain the fuel flow. Similarly, addressing fuel pump defects can help ensure proper fuel pressure, improve efficiency, and prevent other performance problems in forklifts.

To perform a fuel pressure inspection, you’ll need a fuel pressure gauge. First, locate the fuel pump and remove the fuel pressure regulator cap. Attach the fuel pressure gauge to the regulator cap, and then start the forklift to measure the pressure in the fuel system. You can then compare this reading to the manufacturer’s specifications to determine if the pressure is within the proper range.

If fuel pressure is too high, it can cause excessive fuel consumption, engine damage, and even fires. On the other hand, if fuel pressure is too low, it can cause poor engine performance, decreased fuel efficiency, and stalling.

👉 If the error code is resolved, good.
Otherwise, proceed to the next inspection step below.


If the Toyota Forklift is running on LPG/CNG and is displaying error codes E01-3 or E01-4, it could indicate a regulator defect. In this case, the following steps can be taken to perform a regulator primary pressure inspection:

  1. Allow the forklift to cool down by turning it off before starting the inspection.
  2. Locate the pressure regulator on the fuel system.
  3. Disconnect the fuel supply hose from the regulator inlet.
  4. Attach a pressure gauge to the regulator inlet.
  5. Turn on the forklift and let it idle.
  6. Observe the pressure gauge reading and compare it to the manufacturer’s specifications.
  7. If the pressure reading is within the acceptable range, the regulator’s primary pressure is functioning correctly. If not, the regulator may need to be replaced.
  8. Reconnect the fuel supply hose to the regulator inlet and turn off the forklift.

👉 If the error code is resolved, good.
Otherwise, proceed to the next inspection step below.

5). Spark Plug Individual Inspection

The Toyota forklift’s spark plugs are responsible for igniting the fuel-air mixture in its combustion chamber. A well-maintained spark plug with sufficient gap enhances engine performance, preventing misfires.

To ensure the spark plugs are functioning properly, it is important to carry out a spark plug individual inspection. This involves inspecting the spark plug for any signs of wear or damage, such as cracks, carbon deposits, or corrosion. To ensure good engine performance, replace the spark plug if any warning signs appear.

To inspect the spark plugs of a Toyota forklift, follow these steps:

  1. Turn off the engine and let it cool down.
  2. Locate the spark plugs on the engine. The number of spark plugs will depend on the type of engine installed in the forklift.
  3. Remove the spark plug wires or ignition coils to access the spark plugs.
  4. Check the condition of the spark plugs for any signs of wear, damage, or fouling.
  5. If the spark plugs are dirty, clean them with a wire brush or replace them if necessary.
  6. Reconnect the spark plug wires or ignition coils.
  7. Start the engine and ensure that it’s running smoothly without error codes.

👉 If the error code is resolved, good.
Otherwise, proceed to the next inspection step below.

6). Injector Individual Inspection

Injectors are critical components of the engine in a forklift and are responsible for delivering the precise amount of fuel to the engine cylinders.

When a Toyota forklift experiences an error code ranging from E01-1 to E01-4, it could mean that there is a problem with one or more of the injectors.

Inspecting the injectors individually involves removing each injector and checking its condition. Look for signs of wear and tear, damage, or clogging in the nozzle or spray tip. Also, inspect the fuel inlet and outlet ports for any obstructions or blockages. Ensure that the injectors are clean and that the spray pattern is uniform.

👉 If the error code is resolved, good.
Otherwise, proceed to the next inspection step below.

7). Intake Pipe Pressure Sensor Voltage Inspection

The intake pipe pressure sensor is an important component of the engine control system that measures the air pressure in the intake manifold. It provides feedback to the engine control unit (ECU) to adjust the air-fuel mixture and ensure optimal performance. The intake pipe pressure sensor can fail due to various reasons such as wear and tear, damage, or wiring issues. When the sensor fails, it can cause the ECU to receive incorrect data, resulting in the engine running rough and leading to the E01-2 or E01-3 error code.

To diagnose this issue, it is important to inspect the intake pipe pressure sensor voltage. The standard pressure for the intake manifold should be 3.6 ± 0.3 V (100 ± 10 kPa (1 ± 0.1 kgf/cm2) [14 ± 1.4 psi]). If the voltage reading is outside of this range, it indicates a problem with the sensor.

👉 If the error code is resolved, good.
Otherwise, proceed to the next inspection step below.

8). Intake Temperature Sensor Inspection

The Intake Temperature Sensor plays a crucial role in providing the engine control module (ECM) with real-time information about the temperature of the air entering the engine. Based on this information, the ECM can adjust the air-fuel mixture to ensure efficient combustion, which in turn reduces emissions and improves fuel economy.

If the Intake Temperature Sensor is defective or fails, the ECM may not receive accurate information about the temperature of the intake air, which can lead to poor engine performance, increased emissions, and reduced fuel efficiency. As a result, it is important to identify and resolve any issues with the sensor promptly.

An error code is triggered when the ECM detects a voltage signal outside of the expected range from the Intake Temperature Sensor.

To diagnose the issue, the Intake Temperature Sensor voltage should be inspected using a voltmeter. The standard readings for the THA (Intake Air Temperature Sensor) voltage are:

THA2.4 ± 0.6 V (20 ± 10°C)
0.55 ± 0.15 V (80 ± 10°C) (reference value)

If the voltage readings are outside of the expected range, it may indicate a problem with the Intake Temperature Sensor or the wiring connected to it. It is recommended to consult with a qualified technician to diagnose and repair the issue.

👉 If the error code is resolved, good.
Otherwise, proceed to the next inspection step below.

9). Coolant Temperature Sensor Inspection

The Coolant Temperature Sensor is responsible for monitoring the temperature of the coolant in the engine. And sends this information to the engine control module (ECM), which uses it to adjust the air/fuel ratio and other engine parameters. The error code will be triggered if the coolant temperature sensor is malfunctioning or sending inaccurate signals. 

To diagnose the problem, a technician can perform a voltage inspection of the coolant temperature sensor. This involves starting the engine and allowing it to warm up completely, then measuring the voltage output of the sensor using an I/O monitor. The standard readings for the sensor should be:

THW0.55 ± 0.15 V (80 ± 10°C)
2.4 ± 0.6 V (20 ± 10°C) (reference value)

👉 If the error code is resolved, good.
Otherwise, proceed to the next inspection step below.

10). Harness Continuity and Short Circuit Inspection

The harness plays an important role in the operation of the forklift, as it connects the electrical components of the vehicle. If the harness is damaged or has a short circuit, it can cause the forklift to malfunction or display an error code.

To diagnose a harness defect, the harness continuity and short circuit inspection procedure may be followed. This involves checking the wiring for any breaks, damage, or other issues that could interrupt the flow of electrical current. If any problems are found, the wiring may need to be repaired or replaced to resolve the issue.

The standard readings for different connectors should be:

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

👉 If the error code is resolved, good.
Otherwise, proceed to the next inspection step below.

11). 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. If the connector is faulty, it can interfere with the voltage signal and cause the engine control system to receive 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, good.
Otherwise, proceed to the next inspection step below.

12). 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 result in the O2 sensor reading incorrect voltage levels, causing the check engine light to appear, and E01-1, E01-2, E01-3, or E01-4 codes to be generated.

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).


In conclusion, troubleshooting error codes E01-1, E01-2, E01-3, and E01-4 on a Toyota forklift can be challenging, but it is a manageable task. It can be done efficiently with a systematic approach.

These error codes indicate a Fuel Feedback Control Abnormality, which can be easily resolved by identifying and fixing issues with the fuel delivery system.

By following the steps outlined in this guide, you can identify and resolve a range of issues that could be causing these errors, including intake system defects, exhaust system defects, sensor defects, ignition defects, fuel system defects, harness defects, engine controller defects, and more.

Remember to always prioritize safety and seek the help of a qualified technician if necessary.