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Lighting System Diagnostic System Check

  1. Ensure battery condition, cold cranking amperage and reserve capacity meet specifications. Replace as necessary. Install scan tool to Data Link Connector (DLC). If scan tool powers up, go to next step. If scan tool does not power up, go to SCAN TOOL DOES NOT POWER UP  .
  2. Turn ignition on, engine off. Try to establish scan tool communication with BCM. If communication with BCM is established, go to next step. If communication with BCM is not established, go to SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE  .
  3. Select display DTC function for BCM. Record all displayed DTCs and status of displayed DTCs. If DTCs are displayed, go to next step. If no DTCs are displayed, attempt to diagnose system by symptom. Go to SYMPTOM TESTS  .
  4. If scan tool displays any DTCs that begin with "U", go to SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE  . If scan tool does not display any DTCs that begin with "U", go to next step.
  5. If scan tool displays DTC B1000, go to BODY CONTROL MODULE (BCM) DTC DEFINITIONS  . If scan tool does not display DTC B1000, go to next step.
  6. If scan tool displays DTC C1294 or C1295, go to appropriate ANTI-LOCK BRAKE article in BRAKES. If scan tool does not display DTC C1294 or C1295, go to BODY CONTROL MODULE (BCM) DTC DEFINITIONS  table and perform appropriate test.
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