General Information

A built-in, self diagnostic system will identify problems most likely to occur in the Throttle Body Fuel Injection System. When a problem is detected, the diagnostic system will illuminate a ``Check Engine'' or ``Service Engine Soon'' light in the instrument panel. The ``Check Engine'' light will flash a trouble code or codes when a trouble code ``Test'' terminal under the dash is grounded with ignition on and engine not running.
The ``Check Engine'' or ``Service Engine Soon'' light will illuminate with the ignition switch on and the engine not running. If the ``Test'' terminal is then grounded and the light flashes a Code 12, the self-diagnostic system is functioning properly. A Code 12 consists of one flash, a short pause, then two flashes in rapid succession. After a longer pause, the code will repeat two more times.
When the engine is started, the ``Check Engine'' or ``Service Engine Soon'' light should turn off. If the light remains lit, the self-diagnostic system has detected a problem. To determine where the problem exists, ground the ``Test'' terminal with ignition on and engine not running and observe trouble code display. Each trouble code will flash three times in numeric order. Each trouble code will indicate a fault in a particular circuit. To diagnose the problem, refer to procedure given for appropriate trouble code.