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Home >> Pontiac >> 2009 >> G8 Base >> Repair and Diagnosis >> Accessories & Equipment >> Cruise Control Systems >> Diagnostic Information and Procedures >> DTC P0571 >> Circuit/System Testing

Circuit/System Testing

  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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