# P0420 on the 2010 Audi S4

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.

## Bulletins for this model year that name P0420

- [10118327](https://open.wenmarpro.com/bulletins/10118327), 2017-10-04: 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.