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: Equipment and accessories are shown. Show all
| A9121342018187_1 | 2021-10-05. Service bulletin. EQUIPMENT. This bulletin contains inspection guidelines for radio interference that causes noises in the speaker. |
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| A9121332064292_1 | 2021-10-05. Service bulletin. EQUIPMENT. This bulletin contains repair instructions for when adjusting the MMI volume via the steering wheel controls, the volume sporadically and unintentionally goes all the way to min or max. |
| A9121312061028_3 | 2021-10-05. Service bulletin. ELECTRICAL SYSTEM; EQUIPMENT. This bulletin explains and troubleshoots when Audi connect does not have a green SOS light. |
| A9121302062115_6 | 2021-10-05. Service bulletin. EQUIPMENT:ELECTRICAL. This bulletin contains instructions for when the nav files are corrupted during an update. |
| A8721162041717_7 | 2021-10-05. Service bulletin. EQUIPMENT:APPLIANCE:AIR CONDITIONER. This informational bulletin details on how to get a GFF test plan for A/C compressor replacements. |
| A0121102028842_3 | 2021-10-05. Service bulletin. EQUIPMENT:ELECTRICAL. This informational bulletin gives instructions for identifying chip tuning. |
| A4821092028220_9 | 2021-09-03. Service bulletin. EQUIPMENT. This technical service bulletin informs the reader that damage to the appearance of the leather steering wheel caused by outside influence is not covered under warranty. |
| A9121212064246_1 | 2021-09-03. Service bulletin. EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL; EQUIPMENT:ELECTRICAL. This bulletin contains information on how addressing the Bluetooth/address book download. |
| A9121202051720_4 | 2021-09-03. Service bulletin. EQUIPMENT:ELECTRICAL. This bulletin contains instructions for submitting a customer registration form for the Audi phone box to the customer's Mobile Network Operator. |
| A4421832056386_6 | 2021-09-02. Service bulletin. STEERING: STEERING WHEEL/HANDLE BAR; EQUIPMENT; EQUIPMENT ADAPTIVE/MOBILITY. This bulletin contains instructions for when the vehicle pulls to one side or the steering wheel is crooked. |
| A4221462038689_5 | 2021-08-04. Service bulletin. EQUIPMENT; SUSPENSION:REAR. 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. |
| A1921222046712_3 | 2021-08-04. Service bulletin. ENGINE AND ENGINE COOLING; EQUIPMENT; FUEL SYSTEM, GASOLINE:STORAGE:TANK ASSEMBLY:FILLER PIPE AND CAP. This informational bulletin contains guidelines for figuring out why coolant marks are present around the coolant expansion tank cap. |
| 21AUUSMaint721 | 2021-08-04. Service bulletin. EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL. Additional Maintenance Items: Rear axle, quattro Sport - Change ATF and differential oil. CHANGED "Change Fluids". Every 60,000 miles - Only: RS 5, S6, S7, SQ7, SQ8, RS Q8. Oil Capacity Chart: Changed Q7 45 TFSI 2.0L oil type to "508". |
| A9121142053916_3 | 2021-08-04. Service bulletin. ELECTRICAL SYSTEM:SOFTWARE; EQUIPMENT. This informational bulletin contains instructions for when a non-plus sized iPhone heats up while wirelessly charging and the CarPlay screen may appear frozen. |
| A9021092063913_1 | 2021-07-02. Service bulletin. EQUIPMENT; ELECTRICAL SYSTEM: INSTRUMENT CLUSTER/PANEL; ELECTRICAL SYSTEM:SOFTWARE. This bulletin contains a software update for when the cluster's driver information system is blank. |
| A1921192061918_3 | 2021-07-02. Service bulletin. ENGINE AND ENGINE COOLING; EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL. This bulletin provides guidance on diagnosing a coolant light concern with normal coolant level in the tank. |
| A0021482021205_6 | 2021-07-02. Service bulletin. EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL; STRUCTURE. This informational bulletin explains how to order replacement VIN plates, Safety Certification Labels, etc. |
| A9121102062115_5 | 2021-07-02. Service bulletin. EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL; EQUIPMENT:ELECTRICAL:NAVIGATIONAL SYSTEM(GLOBAL POSITIONING SYSTEM). This bulletin contains instructions for when the nav files are corrupted during an update. |
| A9121092063702_1 | 2021-07-02. Service bulletin. ELECTRICAL SYSTEM; EQUIPMENT; EQUIPMENT ADAPTIVE/MOBILITY. This bulletin states to create a PSS when the MMI display turns blue. Workaround provided. |
| A0021472031473_3 | 2021-07-02. Service bulletin. EXTERIOR LIGHTING:HEADLIGHTS:CONCEALMENT DEVICES; EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL; STRUCTURE. This information bulletin states to remove the car wash bristle and advise the customer to go somewhere else to prevent it from occurring again. |
| A9421392063739_1 | 2021-07-02. Service bulletin. EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL; EXTERIOR LIGHTING:HEADLIGHTS:DAYTIME RUNNING LIGHTS:BULBS. This information bulletin explains how the daylights turn on and off. |
| A9121082063290_1 | 2021-07-02. Service bulletin. EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL; ELECTRICAL SYSTEM. This bulletin contains instructions for troubleshooting FoD malfunctions. |
| A4821042063528_1 | 2021-07-02. Service bulletin. ENGINE; EQUIPMENT. This bulletin contains instructions for addressing intermediate shaft noises that are heard in the engine compartment. |
| A4821032063546_1 | 2021-07-02. Service bulletin. EQUIPMENT; STEERING. This bulletin states how to check for a dynamic steering actuator problem. Solution is under development. |
| A4821022061904_3 | 2021-07-02. Service bulletin. STEERING; EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL; ELECTRICAL SYSTEM. This bulletin contains repair instruction for when DTC C110DF0 is stored and the yellow steering lamp is on. |
The summaries are NHTSA's. Each bulletin's page links NHTSA's copy of the manufacturer's document.