P0420 on the 2021 Honda Accord
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.
| ATI&12022024909 | 2024-12-12. Other. Dealer Message - American Honda Motor Co., Inc. (AHM) is searching for certain 2018-2024 Accord 1.5Ls, 2021-2024 Civics 1.5Ls, 2023-2024 CR-Vs 1.5Ls, and 2017 Fits with customer complaint of Check Engine Light (CEL) on with DTC P0420 [Catalyst System Efficiency Below Threshold] stored. To better understand the cause of this condition, AHM would like to specific parts from the vehicle prior to you attempting a repair of any kind. |
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| ATI&11052024902 | 2024-11-14. Other. Dealer Message - American Honda Motor Co., Inc. (AHM) is searching for certain 2018-2024 Accord 1.5Ls, 2021-2024 Civics 1.5Ls, 2023-2024 CR-Vs 1.5Ls, and 2017 Fits with customer complaint of Check Engine Light (CEL) on with DTC P0420 [Catalyst System Effciency Below Threshold] stored. To better understand the cause of this condition, AHM would like to specific parts from the vehicle prior to you attempting a repair of any kind. |
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.