Service bulletins for the 2021 Audi S4
A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.
969 on file from NHTSA, as of 2026-10-19.
By type
By component
By trouble code
Only bulletins with component: Tail lights are shown. Show all
| A9423672071954_1 | 2023-11-06. Service bulletin. EXTERIOR LIGHTING:TAIL LIGHTS; EXTERIOR LIGHTING:HEADLIGHTS. This bulletin provides information pertaining to when there are foreign objects inside of a headlight or taillight. |
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| A9421522065234_1 | 2022-01-06. Service bulletin. EXTERIOR LIGHTING:TAIL LIGHTS. This bulletin contains a software update to address various DTCs regarding a tail lamp warning and the warning may flash quicker after actuation. |
The summaries are NHTSA's. Each bulletin's page links NHTSA's copy of the manufacturer's document.