All vehicles are equipped with a "CHECK ENGINE'' or warning light located on the instrument cluster. This light should come on briefly when the ignition key is turned ON, but should turn off when the engine starts. If the light does not come ON when the ignition key is turned ON or if it comes ON and stays ON when the engine is running, there is a malfunction in the electronic engine control system. After the malfunction has been remedied, using the proper procedures, the "CHECK ENGINE'' light will go out.
Federal and Canadian vehicles are equipped with a mileage sensor which is linked to the odometer. At every 80,000 miles (128,744 km), the mileage sensor will cause the Malfunction Indicator Light (MIL) to illuminate, indicating that the oxygen sensor must be replaced.
After replacing the oxygen sensor, remove the instrument cluster and reset the MIL by reversing the position of the MIL set screw.