Diagnostic Procedure

NOTE: DO NOT skip any steps in self-diagnostic tests or incorrect diagnosis may result. Ensure self-diagnostic tests apply to engine being tested.

If no trouble codes were found while performing BASIC DIAGNOSTIC PROCEDURES in BASIC TESTING proceed with self-diagnostics. Always perform a visual inspection before attempting to diagnose engine control system problems. See VISUAL INSPECTION . Enter on-board diagnostics, and retrieve trouble code(s) using CHECK ENGINE light or DRB. See ENTERING ON-BOARD DIAGNOSTICS . If trouble codes are not present and/or DRB (Diagnostic Readout Box) is used, proceed to TEST TC-1A in this article. Perform indicated VERIFICATION PROCEDURE test after repairs.