P0420 on the 2003 Honda Element
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.
| 604 | 2005-04-28. Service bulletin. UPDATE ECM/PCM FOR DIAGNOSTIC TROUBLE CODE P0420, CATALYST BELOW THRESHOLD. *NM |
|---|---|
| 07012004 | 2005-04-28. Service bulletin. S/M FIX DTC P0420 TROUBLESHOOTING. *EH |
| 03031 | 2003-10-22. Service bulletin. MALFUNCTION INDICATOR LAMP COMES ON WITH DIAGNOSTIC TROUBLE CODE P0420 (CATALYST SYSTEM EFFICIENCY BELOW THRESHOLD). *TT |
| 03031 | 2003-08-14. Service bulletin. MALFUNCTION INDICATOR LAMP ON AND DIAGNOSTIC TROUBLE CODE P0420 (CATALYST SYSTEM EFFICIENCY BELOW THRESHOLD) IS SET. *TT |
4 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.