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Home >> GMC >> 2006 >> Sierra 1500 HD, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1146 (Engine Controls And Fuel - 3.6L - DTC P0008 To DTC P0161) >> DTC P0030, P0031, P0032, P0036, P0037, P0038, P0050, P0051, P0052, P0056, P0057, or P0058 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2008 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the harness connector at the appropriate heated oxygen sensor (HO2S).
  2. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal C and ground.
      IMPORTANT: The ignition circuit supplies voltage to other components. Make sure you test all circuits for a short to ground or test all components for being shorted that share the ignition circuit.
    • If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition circuit fuse is open, test all the components connected to the ignition circuit and replace as necessary.
  3. Connect a test lamp between the heater control circuit terminal D and B+. The test lamp should not illuminate.
    • If the test lamp is always ON, test the control circuit for a short to ground. If the circuit/connections test normal, replace the ECM.
    4. IMPORTANT: The control circuit for the HO2S heater is pulled-up to voltage within the ECM, 2.0-3.0 volts on the control circuit is normal.
  4. Idle the engine, and verify the test lamp illuminates or flashes.
    • If the test lamp is always OFF, test the control circuit for an open/high resistance. If the circuit/connections test normal, replace the ECM.
  5. Ignition ON, test for 2.0-3.0 volts between the control circuit terminal D and ground.
    • If not within the specified range, test the control circuit for a short to voltage. If the circuit/connections test normal, replace the ECM.
  6. If all circuits/connections test normal, test or replace the HO2S sensor.
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