How To Reset Engine Control Module Of Your Car?

The Engine Control Module (ECM) is one of the most critical components found in modern vehicles. It is also known as the Engine Control Unit (ECU) or Powertrain Control Module (PCM). This piece of equipment essentially acts as the main computer system for many of the vehicle’s engine performance and drivability systems.

The various sensors in the engine relay information to the ECM and that information are used to calculate and tune engine spark and fuel for maximum efficiency and power.

Since the ECM is such a critical piece of equipment, when it begins to fail, the car may become undrivable altogether. When problems arise with the ECM, follow the below to know how to reset engine control module.

What Does The ECU Do?

Firstly, it is important that you have to understand what an ECU system is and what it does in your car. Basically, your car’s ECU system intends to learn about your car’s engine as you drive. In this learning process, the ECU tracks tolerance changes of your car engine’s actuators and sensors. Some of these values are the position of the automatic choke while the car is idle, and the injectors’ trim gain as well.

The values that the ECU system learns are stored in the RAM. This RAM is backed up by a battery so that it remains saved even when the engine is off. This means that it reads the saved values every time you turn on your engine, and starts from there.

When you decide to reset your ECU system, you intend to clear all the saved logs and long-term memory that your ECU system has to date. These logs include idle speed, spark, fuel, etc.

How To Reset Engine Control Module?

There are several ways that you can use to reset your ECU successfully. Let us discuss some of them step by step for an easier process to know how to reset engine control module.

1. Resetting Your Faulty Car Computer

This step-by-step guide will come in handy, should you choose to reset your car computer without involving a mechanic or other professional. The reset should restore the ECM to its default settings and clear all car computer-related problems in your vehicles, such as computer codes.

You can use two methods for resetting your car’s computer. The first option is to turn off the car’s battery to break the circuit and erase all memory. On the other hand, you can go about the computer reset procedure with the car battery still on and attached to the car.

2. Resetting The Car Computer With The Battery Turned Off

For this procedure, you would need a battery, wrench or pliers, and insulating tape. You can also prepare a 10-watt resistor. Remember to turn off your car before beginning.

Using the battery wrench, remove the battery terminals. Then remove the battery from its compartment. This will effectively break the circuit. Thus, preventing the flow of power into the engine. Next, short the negative and positive wires of the engine, and tie them together using the insulating tape.

Do the soft reset by leaving the wires short for about 45 minutes. This should drain the circuit of any residue current and cut the power from the car computer. Clean the battery and its terminals using water and baking soda. Ensure to remove all rust, and rinse the battery after cleaning to clean off all the solution. After the 45-min wait, restore the battery and reconnect all the terminals.

Once everything is ready, switch the car back on and inspect the check engine light. The issue should be solved, and the error codes will no longer appear. Your check engine light will be working properly.

3. Resetting The Car Computer With The Battery Turned On

You can also reset your car computer without having to disconnect your car battery. To begin, you will require a fuse puller and a code reader. You could also use a pair of pliers in place of the fuse pullers.

To go about this process, you will need to locate the vehicle’s fuse box. Search for a cover detailing the car’s various fuses. Once you have found it, follow the rest of our steps.

Remove the cover, and using the fuse puller, pull the fuses labeled “Back-up” with 7.5A. Locate another fuse labeled “ECU” and pull it out with 15A. Note that for this procedure, you will not have to disconnect the negative battery terminals.

The problem with following the former process and disconnecting the battery terminals is that you erase your entire car’s memory. This not only solves the issue with the check engine light, but it also resets all other information in your vehicle, including the important data.

Let the fuses remain disconnected for about 10 minutes, then reinstall them properly, alongside the ECU. Restore the fuse box cover and test your vehicle. You can drive for a few minutes to check if the issue of the check engine light has been solved. In case the light stops illuminating, you are good to go.

If the check engine light comes on, reduce your speed and load as you drive on. If available, maximize the built-in diagnostic services that report trouble codes. This will allow you to schedule a service appointment with your automaker.

How To Drive The Car After Resetting ECU?

Once you have reset your ECU system, it is important to drive the car for around 30 minutes to educate it about your driving style. Whether you are interested in increasing its performance or making your car more flexible and economical, drive it in the same style and your ECU system will adapt to your individual driving style.

If you cannot proceed with the reset process by yourself, take the car to the nearby mechanics or auto repair shops.


Car owners should continuously conduct car maintenance for durability and proper functionality. An ECM can show when there are faults, and you can take the step to remedy the situation. Once maintenance and correction procedures are complete, you can now proceed and reset the ECM. Follow the above simple steps to know how to reset engine control module.

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