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 codes. See ENTERING ON-BOARD DIAGNOSTICS . If fault codes are not present and/or using Diagnostic Readout Box II (DRB-II), proceed to one of following tests.

Go to appropriate TEST NS-1A if a no-start condition exists or engine stalls after start-up. Perform indicated VERIFICATION TEST after repairs have been made.
Go to appropriate TEST FC-1A if engine runs but has performance problems. Perform indicated VERIFICATION TEST after repairs have been made.
Go to appropriate TEST NF-1A if a driveability problem exits but no fault codes are present. Perform indicated VERIFICATION TEST after repairs have been made.