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Home >> Hummer >> 2008 >> H2 4D Utility Wagon >> Repair and Diagnosis >> External Pages >> Different car >> Section 508 (Engine Controls/Fuel - 5.3L, 6.0L, 6.2L - DTC P0420 To DTC P3449 And Diagnostic Information And Procedures) >> Diagnostic Information and Procedures >> DTC P2270 or P2272 >> Circuit/System Verification

Circuit/System Verification

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  1. Ignition ON, observe the DTC information with a scan tool. Verify that no HO2S heater DTCs are set.
  2. Engine idling, move the appropriate HO2S 2 harness connector and the engine control module (ECM) harness connector while monitoring the scan tool HO2S 2 voltage parameter. Verify that the HO2S parameter does not change abruptly while moving the related harnesses.
    • If the HO2S parameter does change abruptly while moving the related harnesses repair the circuit as necessary.
  3. Engine idling at operating temperature, observe the appropriate scan tool HO2S voltage parameter. Verify the following:
    • The HO2S 1 value should vary from below 200 mV to above 800 mV and respond to fueling changes.
    • The HO2S 2 value should fluctuate at less than 380 mV or greater than 520 mV. The values should not remain within 380 mV and 520 mV.
  4. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
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