All Systems

If a system fault (malfunction) occurs, a built-in fail-safe mechanism within ECU controls fuel and ignition system functions according to preprogrammed values. This allows vehicle to be driven, but performance may not be optimal. A self-diagnostic function allows ECU to store trouble codes in its memory. If a system fault occurs, CHECK ENGINE light will come on to inform driver of system problems and trouble code will be stored. For further self-diagnostic system information, see TESTS W/CODES article in the ENGINE PERFORMANCE Section.