P0420 on the 2011 Honda Pilot
The bulletins listed name this code in NHTSA's summary, or are about the same components. A bulletin or a recall listed here may apply to the model year. None of it is a diagnosis.
Nobody has written a description of this code yet.
| Service Bulletin | 2018-03-12. Service bulletin. Service bulletin - The MIL is on with DTC P0420 or DTC P0430 (catalyst system efficiency below threshold) with a possible DTC P2243 or DTC P2247 (A/F sensor 1 circuit high voltage). One or both primary A/F Sensor (Air Fuel Ratio) caps may have fallen off and bored a hole through the affected WU-TWC (Warm Up Three Way Catalyst). |
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1 on file from NHTSA, as of 2026-10-19. See them in the bulletin list. A bulletin lists model years: read the document for which vehicles it concerns.