Diagnostic Procedure

NOTE: DO NOT skip any steps in self-diagnostic tests or incorrect diagnosis may result.

Always perform a visual inspection before attempting to diagnose engine control system problems. See VISUAL INSPECTION . Enter on-board diagnostics, and retrieve fault code(s). See ENTERING ON-BOARD DIAGNOSTICS . If fault codes are not present and/or DRB-II (Diagnostic Readout Box-II) is used, proceed to one of the following tests:

Go to TEST NS-1A (NO-START TEST 1A) if a no-start condition exists or engine stalls after start-up. Perform indicated VERIFICATION PROCEDURE test after repairs. Ensure self- diagnostic tests apply to engine being tested.
Go to TEST DR-1A (DRIVEABILITY TEST 1A) if engine runs but has performance problems. Perform indicated VERIFICATION PROCEDURE test after repairs. Ensure self-diagnostic tests apply to engine being tested.
Go to TEST NF-1A (NO FAULT CODE TEST 1A) if a driveability problem exits and no fault codes are present. Perform indicated VERIFICATION PROCEDURE test after repairs. Ensure self-diagnostic tests apply to engine being tested.