P0420 on the 2010 Audi A6
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.
| Elsa Newsletter | 2017-10-04. Service bulletin. TSBs in this newsletters include the MIL on due to DTC P042000 and/or P043000 (Catalyst system Bank 1/2, Efficiency below threshold) being stored in the ECM. New ECM software implemented to correct the condition. |
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1 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.