Vehicle On-Board Diagnostic System Check

The powertrain diagnostic system check determines:

• If Malfunction Indicator Light (MIL) operates.
• If PCM is operating and can recognize a fault.
• If any DTCs are stored.

1. Connect scan tool to Data Link Connector (DLC). Turn ignition on, engine off. If scan tool powers up, go to next step. If scan tool does not power up, see SCAN TOOL DOES NOT POWER UP under appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT. Figure
2. Turn ignition on, engine off. Attempt to establish communication with BCM, Sensing and Diagnostic Module (SDM), PCM and Electronic Brake/Traction Control Module (EBTCM). Record DTCs from each module if possible. If scan tool communicates with BCM, go to step  4 . If scan tool does not communicate with BCM, go to next step.
3. If scan tool communicates with SDM, see DTC U1064: LOST COMMUNICATIONS WITH BODY CONTROL MODULE in appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT. If scan tool does not communicate with SDM, see NO COMMUNICATION ON CLASS II DATA LINK in appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
4. If DTCs are set in BCM, see appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT. If no DTCs are set in BCM, go to next step.
5. If DTCs are set in PCM, see DIAGNOSTIC TROUBLE CODE DEFINITIONS  . If no DTCs are set in PCM, go to next step.
6. If DTCs are set in EBTCM, see appropriate ANTI-LOCK/TCS article in BRAKES. If no DTCs are set in EBTCM, go to next step.
7. Attempt to start engine. If engine does not start and run, see appropriate BASIC DIAGNOSTIC PROCEDURES article. If engine starts and runs, vehicle on-board diagnostics system is complete. Refer to scan tool data to determine if parameters are in correct operating range for system being diagnosed. Also, for symptom diagnostics, see appropriate TROUBLE SHOOTING - NO CODES article.