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Home >> Buick >> 2007 >> Rainier 4.2 S, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 578 (Cruise Control System) >> Diagnostic Information and Procedures >> DTC P1574 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2009 GMC Envoy and 2009 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the harness connector at the stop lamp switch.
  2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal B and ground.
    • If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the signal circuit terminal A for a short to ground.
  3. Verify the scan tool TCC/Cruise Brake Pedal Switch parameter displays Released.
    • If not the specified value, test the signal circuit terminal A for a short to voltage. If the circuit tests normal, replace the ECM.
  4. Install a 3A fused jumper wire between the signal circuit terminal A and the B+ circuit terminal B. Verify the scan tool TCC/Cruise Brake Pedal Switch parameter displays Applied.
    • If not the specified value, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
  5. If all circuits test normal, test or replace the stop lamp switch.