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Home >> Chevrolet >> 2006 >> Impala LTZ >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - 3.9L - DTC P0442 To DTC P2A01 >> DTC P2A01 >> Circuit/System Testing
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Circuit/System Testing

  1. With the engine running at operating temperature, observe the affected HO2S sensor parameter with a scan tool and manipulate the related wiring and connectors. Manipulation should not affect the parameter.
    • If manipulation does affect the parameter, then repair the harness or connector.
  2. With the ignition ON, the engine OFF, and the sensor disconnected, measure for approximately 4 mV from the affected HO2S sensor low signal circuit to ground.
    • If more than approximately 4 mV, test the affected HO2S sensor low signal circuit for a short to voltage or a faulty control module.
    • If less than approximately 4 mV, test the affected HO2S sensor low signal circuit for high resistance or for a faulty control module.
  3. With the ignition ON, the engine OFF, and the sensor disconnected, measure for approximately 412 mV from the affected HO2S sensor high signal circuit to ground.
    • If more than approximately 412 mV, test the affected HO2S sensor high signal circuit for a short to voltage or a faulty control module.
    • If less than approximately 412 mV, test the affected HO2S sensor high signal circuit for a short to ground, high resistance, or for a faulty control module.
  4. With the ignition ON, the engine OFF, and the sensor disconnected, install a 3-amp fused jumper between the affected HO2S sensor high signal circuit and the affected HO2S sensor low signal circuit. The affected HO2S parameter should indicate 0 mV.
    • If all circuits and connectors test normal and the affected HO2S parameter does not indicate 0 mV, replace the control module.
  5. With the ignition ON, the engine OFF, and the sensor disconnected, install a test lamp between the affected HO2S sensor high signal circuit and battery voltage. The affected HO2S parameter should indicate approximately 1106 mV.
    • If all circuits and connectors test normal and the affected HO2S parameter does not indicate 1106 mV, replace the control module.
  6. If the control module and all circuits test normal, replace the affected HO2S sensor.
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