Engine Controls - Tests W/Codes: Introduction: Notes

Most engine control problems result from mechanical failures, poor electrical connections or damaged vacuum hoses. Before condemning the computer system, perform checks and inspections covered in BASIC TESTING article in the ENGINE PERFORMANCE Section. Failure to do so may result in lost diagnostic time.

If no faults were found while performing BASIC DIAGNOSTIC PROCEDURES, proceed with DIAGNOSTIC PROCEDURE. If no fault codes or only a non-running Code 12 is present and driveability problems exist, proceed to TESTS W/O CODES article in the ENGINE PERFORMANCE Section for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.). If only intermittent codes are present, see INTERMITTENTS in TESTS W/O CODES article in the ENGINE PERFORMANCE Section.