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Body Control System Diagnostic Check

NOTE: Use this system check as starting point for any BCM complaint. Most malfunctions are caused by faulty wiring, connectors or components. Use of scan tool is recommended. Follow scan tool manufacturer's instructions.
  1. Turn ignition switch to OFF position. Connect scan tool to Data Link Connector (DLC). Turn ignition switch to ON position, with engine off. Using scan tool, attempt to establish communication with Dash Integration Module (DIM), Instrument Panel Integration Module (IPM) and Rear Integration Module (RIM). If scan tool communicates with modules, go to next step. If scan tool does not communicate with modules, go to step  4 .
  2. Using scan tool, check for DIM, IPM or RIM related DTCs. If any DTC exists, go to next step. If no DTCs exist, system is operating properly at this time.
  3. Check if a class 2 serial data communications related DTCs ("U" codes) are set. If any class 2 DTC is set, go to applicable "U" type code for diagnosis. If other than "U" type DTCs are set, go to appropriate DTC test for diagnosis. See BODY CONTROL SYSTEM DTC DEFINITIONS  table under SELF-DIAGNOSTIC SYSTEM.
  4. Attempt to establish communication with other modules connected to same serial data line (PCM, IPC, etc.). If scan tool communicates with other systems, go to next step. If scan tool does not communicate with other systems, ensure scan tool is operating properly. If scan tool is okay, check Data Link Connector (DLC) circuit. See SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 SERIAL DATA LINE  .
  5. Test module circuits for open or short to ground conditions. See WIRING DIAGRAMS  . If faulty circuits are found, go to step  8 . If circuits are okay, go to next step.
  6. Turn ignition switch to OFF position. Disconnect BCM connectors. Turn ignition switch to ON position. Using a test light connected to ground, probe all module power circuits. If test light comes on at all circuits, go to next step. If test light does not come on at all circuits, go to step  9 .
  7. Locate and repair open in module ground circuit. After repairs, go to step  10 .
  8. Locate and repair open in module power circuit. After repairs, go to step  10 .
  9. Replace one or more of the following modules:

    After repairs, go to next step.

  10. Turn ignition switch to OFF position. Reinstall all components or connectors. Clear DTCs. See CLEARING DTCs  . After clearing DTCs, ensure system is operating properly. If DTCs are set, go to appropriate DTC diagnostic test.
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