P0420 on the 2003 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.
| 1203 | 2005-04-29. Service bulletin. DIAGNOSTIC TROUBLE CODE P0420 AND/OR P0430, CATALYST EFFICIENCY (V6). *NM |
|---|---|
| 604 | 2005-04-28. Service bulletin. UPDATE ECM/PCM FOR DIAGNOSTIC TROUBLE CODE P0420, CATALYST BELOW THRESHOLD. *NM |
| 03063 | 2004-01-02. Service bulletin. MALFUNCTION INDICATOR LAMP COMES ON WITH DIAGNOSTIC TROUBLE CODE (DTC) P0420. *TT |
3 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.