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Home >> Hummer >> 2006 >> H3 Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - 3.5L - DTC P0172 To DTC P0455 >> DTC P0420 >> Repair Procedures
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Repair Procedures

IMPORTANT:
  • Always perform the Diagnostic Repair Verification after completing the diagnostic procedure.
  • A new converter with less than 100 miles on it may set P0420 due to out-gassing of the internal matting. Operating the vehicle at highway speeds for approximately 1 hour may correct the condition.
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