Mike's Workshop Manuals: Service manuals for every vehicle
Home >> Hummer >> 2008 >> H3 Alpha >> Repair and Diagnosis >> Accessories & Equipment >> Cruise Control Systems >> Diagnostic Information and Procedures >> DTC P1574 >> Circuit/System Testing

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the cruise control release switch.
  2. Ignition ON, test for B+ between the B+ circuit terminal 1 and ground.
    • If less than the specified value, test the B+ circuit for a short to ground or an open/high resistance.
  3. Verify the scan tool TCC/Cruise Brake Pedal Switch parameter displays Released.
    • If not the specified value, test the signal circuit terminal 2 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 2 and the B+ circuit terminal 1. Verify the scan tool TCC/Cruise Brake Pedal Switch parameter displays Applied.
    • If not the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
  5. If all circuits test normal, test or replace the cruise control release switch.
scientia non olet · About Mike's Workshop Manuals