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BCM Diagnostic System Check: Testing

  1. Turn ignition off. Connect scan tool to Data Link Connector (DLC). Turn ignition on. Attempt to establish communication with BCM. If scan tool communicates with BCM, go to next step. If scan tool does not communicate with BCM, go to step  7 .
  2. Using scan tool, check for any DTCs that begin with "U" (communication DTCs) stored in BCM. If any communication DTCs exists, go to DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK  . If no communication DTCs exist in BCM, go to next step.
  3. Check for BCM DTCs. If any BCM DTCs exist, go to appropriate diagnostic procedure. See BCM DTC DEFINITIONS  table under SELF-DIAGNOSTIC SYSTEM.
  4. Turn ignition on. Select BCM display on scan tool and monitor CURRENT POWER MODE status. If status is RUN, go to next step. If status is not RUN, go to step  9 .
  5. Monitor CURRENT POWER MODE status on scan tool and turn ignition to start. If status changes to CRANK, go to next step. If status doe not change to CRANK, go to step  9 .
  6. Close driver's and passenger's doors. Monitor CURRENT POWER MODE status on scan tool and turn ignition on and then back off. If status changes to RETAINED POWER, system is operating okay at this time. If status does not change to RETAINED POWER, go to step  9 .
  7. Attempt to establish communication with other systems connected to same serial data line (PCM, RFA, IPC, etc.). If scan tool communicates with other systems, go to next step. If scan tool does not communicate with other systems, go to DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK  .
  8. Turn ignition on. Using a test light connected to ground, probe each BCM fuse. See WIRING DIAGRAMS  . 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  13 .
  9. Turn ignition off. Disconnect BCM 24-pin connector C1, 32-pin connector C2 and 16-pin connector C3. See Figure . Turn ignition on. Using a test light connected to ground, probe each BCM power circuit. See WIRING DIAGRAMS  . 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  15 .
  10. Using a test light connected to battery voltage, probe each BCM ground circuit. See WIRING DIAGRAMS  . 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  16 .
  11. Using DVOM, check for continuity between BCM harness connector C1 terminal B6 (Light Green wire) and Data Link Connector (DLC) terminal No. 2 (Purple wire). If continuity exists, go to next step. If continuity does not exist, go to step  14 .
  12. Replace BCM. See BODY CONTROL MODULE (BCM)  under REMOVAL & INSTALLATION. Reprogram BCM. See BCM PROGRAMMING/RPO CONFIGURATION  under PROGRAMMING. After repairs, go to step  17 .
  13. Check appropriate fuse. If fuse is okay, repair open in ignition or battery feed to BCM fuse. If fuse is blown, locate and repair short in associated circuit. After repairs, go to step  17 .
  14. Locate and repair open in Light Green or Purple wire between BCM connector C1 and DLC. After repairs, go to step  17 .
  15. Locate and repair open in BCM power circuit. After repairs, go to step  17 .
  16. Locate and repair open in BCM ground circuit. After repairs, go to next step.
  17. Turn ignition off. Reinstall all components or connectors. Clear DTCs. Ensure system is operating properly.
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