P0420 on the 2001 Toyota Highlander
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.
| 04105 | 2007-01-24. Service bulletin. ECM CALIBRATION UPDATE. MIL ON DTC P0420 AND/OR P0430. *KB |
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| 00603 | 2003-07-31. Service bulletin. ENGINE CONTROL MODULE (ECM) CALIBRATION UPDATE: MALFUNCTION INDICATOR LAMP ON WITH DIAGNOSTIC TROUBLE CODE P0420 OR P0430. *TT *JB |
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.