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Home >> GMC >> 2006 >> Envoy 4.2 S, 4WD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - 4.2L - DTC P0135 To P0418 >> DTC P0411 >> Circuit/System Testing

Circuit/System Testing

  1. With the engine running, the AIR pump outlet hose disconnected from the AIR solenoid inlet, and the AIR pump enabled with a scan tool, observe pressurized airflow at the hose outlet.
    • If pressurized airflow is not detected, test the AIR pump inlet and outlet hoses/pipes for a restriction or a faulty pump.
  2. With the ignition ON, the engine OFF, and the AIR solenoid substituted with a test lamp, observe that the test lamp is not illuminated.
    • If the test lamp is illuminated, test for the following:
      • A short to voltage in the AIR solenoid valve voltage supply circuit
      • A short to ground in the AIR solenoid valve relay control circuit
      • A faulty AIR solenoid valve relay
      • A faulty control module
  3. With the engine running, the AIR solenoid substituted with a test lamp, and the AIR solenoid enabled with a scan tool, observe that the test lamp is illuminated.
    • If the test lamp is not illuminated, test for the following:
      • High resistance or a short to ground in the AIR solenoid voltage supply circuit or either AIR solenoid relay voltage supply circuit
      • High resistance in the AIR solenoid ground circuit
      • A faulty AIR solenoid relay
      • High resistance or a short to voltage in the AIR solenoid relay control circuit
      • A faulty control module
  4. Test the AIR solenoid outlet pipe for a restriction.
    • If a restriction is detected, remove the restriction or replace the pipe.
  5. If all other circuits and components test OK, replace the AIR solenoid.