How to Reset Check Engine Light?: 8 Methods

Table of Contents

1 How to Reset Check Engine Light
2 FAQ Section

The check engine light usually illuminates when there’s an issue with your car’s emission control system or another electronically managed system. However, if the light remains on even after addressing the problem, it can be puzzling. Chances are, you simply need to reset the check engine light, so don’t stress too much. Although there could still be a lingering issue, it’s highly likely that a reset will resolve the issue. This article explains how to fix or reset the check engine light.

How to Reset Check Engine Light

Using an OBD-II scanner to reset the check engine light is one of the easiest methods. You can also reset it by just disconnecting the battery terminal.

You can use one or more below-given methods to reset the check engine light:

Use an OBD-II Scanner
Battery Disconnection Method
Turn the Ignition Key On and Off
Add More Coolant
Replace the Faulty Sensor
Add More Transmission Fluid
Pulling Off the Fuse and Put It Back
Let it Go Off Itself

1) Use an OBD-II Scanner

If you have access to an OBD-II scanner, resetting your check engine light can be done in just a few seconds.

To do so, connect your scanner to the OBD port, typically located underneath the steering area of the vehicle.
Next, turn your vehicle’s ignition to the ON position. Once connected, press the “read” button on the OBD-II to retrieve all saved fault codes.
Upon completing the scan, note all trouble codes. Consult the vehicle manual for your vehicle model to decode these issues.
After decoding the trouble codes and identifying the problem, address it accordingly by replacing parts or calibrating as needed.
After resolving the issue, clear the memory of your vehicle computer by pressing the “Erase/Clear” button on the scanner.
After fixing the issue, it’s advisable to turn off the ignition switch, then turn it back on, and ensure the check engine light doesn’t reappear. Finally, verify with the OBD-II whether the same trouble code is still present or not.

2) Battery Disconnection Method

Resetting the check engine light without an OBD-II scanner can often be done by disconnecting the battery terminals for about 30 to 60 seconds. You can use this method for all vehicles.

Follow the below-given steps to reset the check engine light by disconnecting the battery terminal:

Begin by removing the negative terminal of your battery.
Attempt to discharge any remaining electricity in the capacitor of your vehicle by turning on the headlights or radio for approximately 18 to 40 seconds.
After removing the terminal, let your car sit for about 8 to 16 minutes.
Following this brief period, connect the negative terminal of the battery again, ensuring it is securely fastened to prevent any potential sparking.
Finally, let’s start your vehicle.

If the check engine light reappears after restarting your vehicle, it could indicate a more severe issue or your car may retain the codes regardless. In such instances, it is strongly advised to use a scanner to check the stored trouble code, as some vehicles don’t reset the codes by merely disconnecting the battery.

3) Turn the Ignition Key On and Off

Another simplest method to reset the check engine light without removing the battery terminals involves turning the ignition switch on and off. Insert your ignition key into the ignition switch and quickly switch the ignition on and off, spending a second at each step.

After completing this process, check if the check engine light is still illuminated. If it’s off, you’re good to go; otherwise, be prepared to read the trouble code using a scan tool.

4) Add More Coolant

Insufficient coolant is a frequent cause of a flashing check engine light. When the coolant level in your car drops below a certain threshold, the light illuminates, signaling a low coolant level warning. In this situation, it’s necessary to refill the coolant.

5) Replace the Faulty Sensor

The vehicle’s powertrain control module (PCM) continuously monitors the performance of all sensors while you drive. If any of these sensors malfunctions, the PCM activates the check engine light to notify the driver. Replacing the bad sensor is required to reset the check engine light.

6) Add More Transmission Fluid

If the transmission fluid level falls below a definite threshold, the PCM of your vehicle activates the check engine light to alert you. In such conditions, properly inspect your vehicle’s transmission fluid and add more if necessary.

7) Pulling Off the Fuse and Put It Back

Another method to reset the check engine light is by removing and reinserting the fuse of the engine control unit. While this may not resolve the issue in the latest vehicle models but it could work in older vehicles and is worth a try.

Consult your repair manual to locate the appropriate fuse for your engine control unit.

8) Let it Go Off Itself

An alternative method for resetting the check engine light is to simply wait for it to turn off by itself. This approach requires patience; continue driving your vehicle for about 2-3 days. The vehicle’s computer operates in a continuous cycle, constantly updating its current state.

Keep in mind that the issue must be resolved before employing this method. For instance, if your powertrain control module (PCM) monitors an oxygen sensor issue caused by a small bug, it may automatically correct the status of the sensor once the bug is fixed and will turn off the check engine light.

However, if the light remains on after 2-3 days, you should try the previously mentioned techniques yourself or consult a professional.

FAQ Section

Can I reset the check engine light without disconnecting the battery?

Yes, you can use an OBD-II scanner to reset your vehicle’s check engine light without disconnecting the battery. Additionally, in most car models, the check engine light will clear on its own if you drive long enough after addressing the issue.

Can my check engine light go off by itself?

In most vehicles, the check engine light resets itself after a predetermined amount of time, assuming the issue has been fixed. This usually takes 12 to 30 cycles, with each cycle consisting of starting the engine cold and allowing it to reach working temperature.

How long does it take for the check engine light to reset?

If you’re confident that the issue has been resolved, it typically takes about 12 to 30 successful cycles for the check engine light to turn off. A successful cycle refers to the process of starting the engine cold and driving until it reaches its operating temperature.

How to reset the check engine light without a scanner?

To reset the check engine light without a scan tool, fix the issue and drive your vehicle for a long distance. In some vehicles, disconnecting the negative terminal of the battery can also reset the PCM.

Is it okay to erase the check engine light?

Yes, it is okay to reset the check engine light, provided you have fixed the original issue forcing it to activate. If the issue is still unresolved, your light will be expected to reappear, representing the need for further attention.

How to turn check engine light off?

Use an OBD-II Scanner
Battery Disconnection Method
Turn the Ignition Key On and Off
Add More Coolant
Replace the Faulty Sensor
Add More Transmission Fluid
Pulling Off the Fuse and Put It Back
Let it Go Off Itself

What causes the check engine light to come on?

Insufficient engine oil
Faulty MAP sensor
Faulty ECM
Damaged spark plugs
Faulty catalytic converter
Faulty oxygen sensor
Bad MAF sensor
Insufficient engine coolant
Engine misfiring
Insufficient transmission fluid
Engine overheating
Faulty charging system
Bad EGR valve
Bad fuel injector
Bad crankshaft sensor
Bad camshaft sensor

Written By

Engineer Rahela

Rahela is the owner and main author of Mechanicalspecial. She is an automotive expert writer. She have over four years of experience in the automotive writing niche and have completed over 700 pieces of content from 40 projects. She have good knowledge and skill in vehicle repairing, all mechanical work, car upgrades and maintenance.