Sometimes people think that if you reset the computer, or electronic control module, in your car, it will fix the problems that your engine light is warning you about. It won’t. The engine light is warning you that a sensor has sent a signal to the ECM that it is out of specification and should be checked.
If you have checked and repaired the problem, it may be necessary to erase diagnostic trouble codes if the engine light stays on. The best way to do this would be with a scanner, but if you don’t have one, disconnecting the battery will do the trick on many vehicles.
However, disconnecting the battery will not only erase diagnostic trouble codes but also erase drivability, security and radio codes in many vehicles. Locate any codes and have them and the drivability learning procedures on hand before disconnecting the battery.