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. Resetting the Car Computer with the Battery Turned Off
Can I reprogram my own ECM?
Reprogramming your ECM is necessary for keeping your vehicle control software up to date. Much like the operating system on your home computer, improvements in software are often made by your car's manufacturer. The software can be updated simply by downloading and installing the latest version.
Can you reset the computer in your car?
Do you have to have a PCM programmed?
PCM Reprogramming is also necessary to change the engine idle speed, spark timing, fuel mixture or other emission control functions. PCM Reprogramming may be required to resolve a hot or cold starting issue, idle roughness, stalling, or an emissions failure.