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Home >> Saturn >> 2006 >> Relay 3.5 L, AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - 3.5L - DTC P0220 To DTC P0455 >> DTC P0403 >> Circuit/System Testing
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Circuit/System Testing

  1. Disconnect the EGR valve harness connector and probe the EGR high control circuit with a test lamp connected to ground. Command the EGR valve from 0-10 percent and back to 0 percent. The test lamp should illuminate when commanded to 10 percent.
    • If the test lamp remains illuminated when commanded to 0 percent, test the EGR high control circuit for a short to voltage.
    • If the test lamp does not illuminate, test the EGR high control circuit for an open, high resistance, or short to ground. If the circuit tests normal, replace the control module.
  2. Connect a test lamp between the EGR high control circuit and the EGR low control circuit. Command the EGR valve from 0-10 percent and back to 0 percent. The test lamp should illuminate when commanded to 10 percent.
    • If the test lamp illuminates when commanded to 10 percent, replace the EGR valve.
    • If the test lamp does not illuminate, test the EGR low control circuit for an open or high resistance.
    • If all circuits test OK, replace the control module.
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