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Service bulletins for the 2021 Audi A4

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.

1057 on file from NHTSA, as of 2026-10-19.

By type

By component

By trouble code

Only bulletins with component: Turbocharger or supercharger are shown. Show all

Bulletins, newest first
A0124142071243_22024-04-04. Service bulletin. ENGINE; ENGINE AND ENGINE COOLING:ENGINE:GASOLINE:TURBO/SUPERCHARGER. This bulletin provides information when there are whistling noises from the turbo charger at 1500 - 2200 RPM, and approximately 70% load.

The summaries are NHTSA's. Each bulletin's page links NHTSA's copy of the manufacturer's document.