LEMON Manuals: Even more car manuals for everyone
Home >> Buick >> 2007 >> Lucerne CXL, 3.8 2 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls And Fuel - 3.8L - DTC P0350 To DTC P0607 >> DTC P0403 >> Circuit/System Testing

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 percent to 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 test 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 percent to 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, high resistance.
    • If all circuits test normal, replace the control module.
scientia non olet · About LEMON Manuals