P0420 on the 2018 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.
| ONLN9403292021 | 2021-04-06. Service bulletin. "Owner Notification Letter - On some 2017-19 Pilot, 2017-19 Ridgeline, and 2018-19 Odyssey models, the malfunction indicator light (MIL) may come on if one or more of the following diagnostic trouble codes (DTCs) are stored: - P0420 (rear bank catalyst system efficiency below threshold [bank 1]) - P0430 (front bank catalyst system efficiency below threshold [bank 2]) - P0300-P0306 (misfire) - P219A (air-fuel ratio variation of cylinder [bank 1, rear bank]) - P219B (air-fuel ratio variation of cylinder [bank 2, front bank]) American Honda is extending the warranty on the fuel injectors to 10 years from the original date of purchase or 150,000 miles, whichever comes first. This warranty extension provides coverage for the original owner and any subsequent owners. No action is required on your part unless you experience a problem." |
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| A21-010 | 2021-02-18. Service bulletin. "Service Bulletin - The PCM software may misinterpret sensor inputs as a deteriorated catalytic converter. Additionally, debris from the high pressure pump or the fuel injector machining process can cause internal wear or clogging inside one or more injectors. One or more of the following DTCs may be stored: - P0420 (rear bank catalyst system efficiency below threshold [bank 1]) - P0430 (front bank catalyst system efficiency below threshold [bank 2]) - P0300-P0306 (misfire) - P219A (air-fuel ratio variation of cylinder [bank 1, rear bank]) - P219B (air-fuel ratio variation of cylinder [bank 2, front bank]) American Honda is extending the warranty on these repairs to 10 years from the original date of purchase or 150,000 miles, whichever comes first." |
2 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.