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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

Bulletins, newest first
A0120832060429_12020-09-03. Service bulletin. EQUIPMENT; ENGINE AND ENGINE COOLING:EXHAUST SYSTEM. This bulletin contains instructions for when there may be a noise from the exhaust flap or there are DTCs sporadically stored in the ECM.
A9120922053916_22020-09-03. Service bulletin. ELECTRICAL SYSTEM. This informational bulletin contains instructions for when a non-plus sized iPhone heats up while wirelessly charging and the CarPlay screen may appear frozen.
A6920562059223_22020-09-03. Service bulletin. ELECTRICAL SYSTEM; EQUIPMENT. This bulletin contains information regarding the replacement of PODs components.
A0120762054893_32020-09-03. Service bulletin. ENGINE AND ENGINE COOLING:ENGINE:OIL/LUBRICATION. This bulletin contains instructions for documenting the "Please reduce Oil Level" message in the instrument cluster potentially with an Engine Warmup request.
2010-2021EngOil2020-09-03. Service bulletin. ENGINE; EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL. New document
Audi Part Labels2020-09-03. Service bulletin. EQUIPMENT. Recall Reminder Part Labels
A4020132059474_22020-08-06. Service bulletin. SUSPENSION:FRONT:SHOCK ABSORBER; EQUIPMENT. This bulletin contains instructions for correcting buffer stop noise (rumbling or squeaking from the front end).
21A4S4TCHREP7272020-08-06. Service bulletin. ELECTRICAL SYSTEM. Vehicle Preparation Section: REMOVED: "Perform TSB 2058096/1 '91 Audi connect has no function, SOS LED is off, and SOS warning message in FPK' Perform MMI Menu Reset: 5F-Information Electronics >> Guided Functions >> Basic Settings >> Reset MMI Menu Settings Deactivate privacy mode: Main Menu >> Privacy >> Activate Privacy Settings (Turn off) Turn Vehicle Off and allow Bus Sleep Cycle
A9120842060194_12020-08-06. Service bulletin. EQUIPMENT; ELECTRICAL SYSTEM:SOFTWARE; ELECTRICAL SYSTEM:INSTRUMENT PANEL:FUEL GAUGE:FUEL LEVEL FLOAT/SENSOR/SENDING UNIT. This bulletin states to create a PSS for when the Gas pop-up is blank.
21VEHCONDREP7132020-08-06. Service bulletin. EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL. New Document
21TIREPRSTBL062020-08-06. Service bulletin. EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL; TIRES:PRESSURE MONITORING AND REGULATING SYSTEMS. New Document
21TechRefGde6302020-08-06. Service bulletin. EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL. New Document
21DETAILREPT7132020-08-06. Service bulletin. EQUIPMENT. New Document
21A4S4TECHREP2020-08-06. Service bulletin. EQUIPMENT. New Document
21A4S4ALRDCSDEL2020-08-06. Service bulletin. EQUIPMENT. New Document
A1920042025303_12020-07-07. Service bulletin. ENGINE AND ENGINE COOLING. This bulletin contains instructions for identifying and mixing factory fill coolants.
A9020512058077_42020-07-07. Service bulletin. ELECTRICAL SYSTEM. This bulletin contains instructions for determining unexpected Audi pre sense interventions.
A0020382039206_32020-07-07. Service bulletin. EQUIPMENT; ELECTRICAL SYSTEM. This informational bulletin contains instructions on how to use the QR code in a TSB.
A9120702044694_22020-06-04. Service bulletin. EQUIPMENT. This technical service bulletin provides troubleshooting for issues with the navigation map database.
A9120652036576_62020-06-04. Service bulletin. EQUIPMENT. This informational bulletin contains instructions for when a phone is connected to the vehicle via Bluetooth, one of the following conditions occurs when the user searches for a contact name in the MMI address book (by using the MMI control knob or the voice recognition system): *The MMI screen goes blank then restarts. *The MMI screen freezes for a few minutes then recovers.
A6420742020552_92020-06-04. Service bulletin. VISIBILITY:WINDSHIELD; EQUIPMENT. This bulletin provides instructions on how to clean exterior glass.
A4220442038689_42020-06-04. Service bulletin. EQUIPMENT; SUSPENSION. This bulletin contains information on how to fix a clunking or rattling noise heard from the rear suspension when the vehicle is driven over bumps.
A4020062059474_12020-06-04. Service bulletin. EQUIPMENT; EQUIPMENT ADAPTIVE/MOBILITY; SUSPENSION. This bulletin contains instructions for correcting buffer stop noise (rumbling or squeaking from the front end).
A4020052024318_92020-06-04. Service bulletin. EQUIPMENT; WHEELS. This technical service bulletin provides instructions for correcting a clicking sound from the wheel bearing(s).
A9020452059335_12020-05-07. Service bulletin. ELECTRICAL SYSTEM. This bulletin contains information on noises from the instrument cluster installation area.

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