P0420 on the 2003 Honda Civic
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.
| 1204 | 2005-12-15. Service bulletin. DIAGNOSTIC TROUBLE CODE P0420 AND P1420 REPAIRS. *TT |
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| 05028 | 2005-11-15. Service bulletin. PRODUCT UPDATE: ECM UPDATE TO PREVENT CATALYST DTC P0420 AND/OR VPS DTC P1021, MCM UPDATE TO CURRENT SPECIFICATIONS. *TT |
| 01012005 | 2005-05-09. Service bulletin. REPLACE THE CORRECT THREE WAY CATALYTIC CONVERTER FOR DTC P0420 P01420 P2000. *EH |
| 113004 | 2005-02-01. Service bulletin. DIAGNOSTIC TROUBLE CODE P0420 AND DATA RECORDER INSTALLATION. INVESTIGATION OF 2001-2003 CIVICS WITH THE MALFUNCTION INDICATOR LIGHT (MIL) ON AND DIAGNOSTIC TROUBLE CODE (DTC) P0420 STORED. *NM |
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.