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Home >> Buick >> 2011 >> Lucerne CX >> Repair and Diagnosis >> External Pages >> Different car >> Section 249 (Lighting System) >> Diagnostic Information and Procedures >> DTC C0297 >> Circuit/System Testing
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Circuit/System Testing

WARNING: This page is about a different car, the 2011 Cadillac DTS. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the harness connectors at the control modules listed below:
    • ECM X1
    • TCM
  2. Connect a test lamp between the TCM signal circuit terminal 42 and ground.
  3. Ignition ON, command the stop lamps ON and OFF by applying and releasing the brake pedal. The test lamp should turn ON and OFF when changing between the commanded states.
    • If the test lamp is always ON, test the signal circuit for a short to voltage. If the circuit test normal, replace the BCM.
    • If the test lamp is always OFF, test the signal circuit for a short to ground or an open/high resistance. If the circuit test normal, replace the BCM.
  4. Ignition OFF, connect the harness connector at the TCM.
  5. Connect a test lamp between the ECM signal circuit terminal 7 X1 and ground.
  6. Ignition ON, command the stop lamps ON and OFF by applying and releasing the brake pedal. The test lamp should turn ON and OFF when changing between the commanded states.
    • If the test lamp is always OFF, test the signal circuit for a short to ground or an open/high resistance. If the circuit test normal, replace the TCM
  7. If all circuits test normal, replace the ECM.
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