Check Engine Light Reset Procedure

Check engine light reset The check engine light reset procedure can go down 2 paths. You can use a code scanner to retrieve and clear the codes, which is the proper method. Or you could disconnect the battery and drain the memory holding capacitor in the computer to clear it that way. I will explain both for you, but I only recommend using a scan tool. Note I added an auto repair video explanation at the bottom. If you disconnect the vehicle's battery this alone may not clear codes. Some manufacturers store voltage in a capacitor to hold the computer's memory. After the battery is disconnected you can hold down on the horn button to drain the small amount of electrical energy. This circuit is hot at all times regardless of key position. Doing this will definitely achieve the check engine light reset you were looking for. But there might also be some annoying side effects to the procedure. The vehicle's main computer (PCM) stores the diagnostic trouble codes and also holds what is called the learned memory for a few other important items. The main ones are transmission shift points and idle step position memory. If you reset the check engine light by disconnecting the battery you clear out these important memory functions. This is not something that can't be overcome with some patience! The main on-board computer will have to relearn these import settings. What this means for you is when you restart the vehicle you may have erratic idle and poor performance for several driving cycles after the check engine light resetting procedure was performed.