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Home >> Hummer >> 2008 >> H2 4D Utility Wagon >> Repair and Diagnosis >> External Pages >> Different car >> Section 145 (Engine Control System & Fuel - 4.8L, 5.3L, 6.0L And 6.2L - DTC P0335 To DTC P3449) >> DTC P0420 or P0430 >> Repair Verification

Repair Verification

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  1. Allow the engine coolant temperature to reach 70°C (156°F).
    • Place the gear selector in Park, Neutral for manual.
    • Set the parking brake.
  2. Press and hold the service brake.
  3. Run the engine for 6 minutes at 2500 RPM.
  4. Allow engine speed to return to idle speed, then place gear selector into Drive, or apply clutch pedal for manual.
  5. After 2 minutes verify that DTC P0420 or P0430 have passed or failed this ignition cycle.
    • If not passed or failed this ignition cycle, the test aborted resulting in an inconclusive test result. The above test may need to be repeated up to 5 more times during this drive cycle. The first test should be run after the initial warm up period of 6 minutes. Between subsequent tests maintain 2,500 RPM for 2 minutes.
  6. If 6 tests have been attempted and the DTC has not run or passed during this key cycle, turn the key to OFF for 30 seconds, then run the procedure a second time.
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