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Home >> Pontiac >> 2009 >> G8 Base >> Repair and Diagnosis >> External Pages >> Different car >> Section 69 (Cruise Control System) >> Diagnostic Information and Procedures >> DTC P0571 >> Circuit/System Testing
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Circuit/System Testing

WARNING: This page is about a different car, the 2008 Pontiac G8. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the harness connectors at the appropriate control modules listed below.
    • ECM X1 (L76)
    • ECM X2 (LY7)
    • TCM
  2. Connect a test lamp between the appropriate signal circuit terminal listed below and ground.
    • ECM terminal 9 (L76)
    • ECM terminal 52 (LY7)
    • TCM terminal 6 (L76)
    • TCM terminal 38 (LY7)
  3. Ignition ON, press and release the brake pedal. Verify the test lamp turns ON and OFF when pressing and releasing the brake pedal.
    • If the test lamp is always ON, test the signal circuit for a short to voltage. If the circuit tests 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 tests normal, replace the BCM.
  4. Ignition OFF, connect the harness connector at the TCM.
  5. Connect a test lamp between the appropriate signal circuit terminal listed below and ground.
    • ECM X1 terminal 9 (L76)
    • ECM X2 terminal 52 (LY7)
  6. Ignition ON, press and release the brake pedal. Verify the test lamp turns ON and OFF when pressing and releasing the brake pedal.
    • If the test lamp is always ON, test the signal circuit for a short to voltage. If the circuit tests normal, replace the TCM.
    • If the test lamp is always OFF, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the TCM.
  7. If all circuits test normal, replace the ECM.
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