Engine Controls - Tests W/Codes: Summary
If no hard trouble codes are present (or only pass trouble codes), driveability symptoms exist or intermittent trouble codes exist, proceed to TESTS W/O CODES article for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.) or intermittent procedures.
NOTE:
To determine a common cause for a trouble code to be set, see TROUBLE CODE DIAGNOSTIC HINTS table below.