How to Turn Off The Check Engine Lightby Don Bowman
The automotive computer is designed to recognize any abnormal signal indicating a failure of one of the components it operates. In response to this signal, the computer will assign a failure code to the fault and illuminate the check engine light. The light just indicates that a code is present. The only way to access this code and decipher it is to have a code scanner. Scanners have become quite inexpensive and can be purchased at any auto parts store. They are designed to interface with the computer via the on board diagnostic, or OBD, port. The code can then be displayed and deciphered. To erase a code the problem must be repaired first.
Plug the code scanner cable into the OBD port located to the left of the steering column under the dash on most vehicles. Some foreign cars have the port located on the right side of the column or behind the ashtray. It will always be close to the steering column. If you can't find it, look in the owner's manual.
Turn the ignition key to the "On" position without starting the engine. Depress the "Read" key on the code scanner. It will take a few seconds to interrogate the computer. It will display a letter followed by four numbers. Make a note of this code. Any additional codes will be displayed after a short pause.
Cross-reference these numbers with the accompanying code sheet. The code and its description will be given. It will also give a description of the probable cause in terms of what type of failure the part is experiencing.
Repair the fault before attempting to reset the computer. If the fault is still present the light will come back on immediately, anyway. Turn the ignition key on and press the "Erase" key. The code will be erased from memory and the check engine light will go off.