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Home >> Cadillac >> 2006 >> STS V >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - 4.4L - DTC P0196 To P0496 >> DTC P023A >> Circuit/System Testing
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Circuit/System Testing

  1. Ignition OFF, disconnect the CAC coolant pump relay.
  2. Ignition ON, verify that a test lamp does not illuminate between the control circuit and ground.
    • If the test lamp illuminates, test the control circuit for a short to voltage.
  3. Verify that a test lamp illuminates between the coil voltage supply circuit and ground.
    • If the test lamp does not illuminate, test the B+ coil supply circuit for a short to ground or an open/high resistance.
  4. Verify that a test lamp illuminates between the B+ switch supply circuit and ground.
    • If the test lamp does not illuminate, test the B+ switch supply circuit for an open/high resistance. If the circuit tests normal and the B+ switch supply circuit fuse is open, test the CAC pump voltage supply circuit for a short to ground.
  5. Disconnect the harness connector at the CAC coolant pump.
  6. Test for less than 2 ohm of resistance between the CAC coolant pump ground circuit terminal 1 and ground.
    • If greater than the specified range, repair the ground circuit for an open/high resistance.
  7. Connect the harness connector at the CAC coolant pump.
  8. Connect a 10A fused jumper wire between the B+ switch circuit and the CAC coolant pump voltage supply circuit. Verify that CAC coolant pump is activated.
    • If the CAC coolant pump does not activate, test the CAC coolant voltage supply circuit for an open/high resistance. If the circuit tests normal, test the CAC coolant pump motor. Refer to Component Testing.
  9. Connect a test lamp between the B+ coil supply circuit and the CAC relay control circuit.
  10. Command the CAC coolant pump ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between commanded states.
    • If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the ECM.
    • If the test lamp is always OFF, test the control circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
  11. If all circuits test normal, test the CAC coolant pump relay. Refer to Component Testing.
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