How to Reset your ECU System

How to Reset your ECU System

Most cars are intended to drive in different areas of the world, by men and women of different ages, and levels of driving skills. Different car models can operate at different temperature, terrains and altitudes, and they use varying fuels with different purity and octane ratings. That being said, the ECU or Electronic Control Unit of cars is pre-set to suit the requirements of all, and it can be adapted to the individual driving style of its owners. Many people think that they have no control over their vehicle’s ECU system, but that is not the case. This oneHOWTO article will instruct a car owner on how to reset your ECU system, that too without the company noticing it or without damaging your car’s warranty.

What does the ECU do?

First of all, it is important 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 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 only, instead of starting from zero. 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 till date. These logs include idle speed, spark, fuel etc. Trouble codes are also saved in the ECU system for diagnostic purposes. When you reset your ECU, you will set these values to a neutral default, and also clear all the saved trouble codes.


Step by step instructions to reset your ECU system

Now that you have made up your mind to reset your ECU system, just follow these instructions and be safe:

  1. Drive your car for around 15 minutes to bring it to its normal operating temperature.
  2. Now stop, open your car’s bonnet and remove the lead of earth from the battery. Make sure that the end of the lead is not in contact with any other metal surface of your car
  3. Wait for 5 minutes.
  4. Depress the brake for around 20 seconds so as to completely discharge the capacitors of the ECU system through brake lights. Now, your ECU system has lost all of its saved memory.
  5. Now, reconnect the lead of earth to the battery and close the bonnet.

The basic step towards resetting the ECU system is to remove the backup power source altogether. To keep the values saved, cars have a fuse that goes right into the battery. Usually, this is the same fuse and line that powers up your radio.

Another way to reset your ECU system

Instead of opening your bonnet and removing the earth lead, you can also disconnect the battery from your car by pulling the fuse that powers up your radio or footlights. You can find this fuse near your fuse box, usually on the lower right hand side of your footlight controls. Follow these step by step instructions for this method:

  1. Pull out your car’s key
  2. Pull out the fuse as well
  3. Wait for 15 seconds and put it back in

This is an easier way of removing any long term memory saved in your car’s ECU system.

Drive the car after resetting

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 want to read similar articles to How to Reset your ECU System, we recommend you visit our Car Maintenance and Repair category.