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
| SM 17-2021 | 2021-04-06. Service bulletin. ELECTRICAL SYSTEM. This special notice is to inform dealers to return the parts listed if it meets the criteria provided. |
|---|---|
| A9121762037809_8 | 2021-04-06. Service bulletin. EQUIPMENT. This informational bulletin contains instructions about updating the navigation map. |
| A1921122061918_2 | 2021-04-06. Service bulletin. ENGINE AND ENGINE COOLING. This bulletin provides guidance on diagnosing a coolant light concern with normal coolant level in the tank. |
| A5721742058452_2 | 2021-03-04. Service bulletin. VISIBILITY. This bulletin contains repair instructions for when the rear window defog button will light up and then turn off. |
| 21TechRefGde221 | 2021-03-04. Service bulletin. EQUIPMENT. Q5: Vehicle Prepartion Section: REMOVED: "Set adaption channel to enable CD Ripping using Guided Functions" Settings Section: REMOVED: "(if equipped)" from Turn off Manual Speed Warning On Hoist Inspection Section: ADDED to Install Wheel Bolt Covers: "When installing, ensure proper alignment to the valve stem (indentation in the wheel) lines up with the tab on the center cap to ensure correct mounting" Driver Assistance Section: REMOVED "(if equipped)" from "Verify operation of parking system" |
| A4721082055646_2 | 2021-03-04. Service bulletin. SERVICE BRAKES. This bulletin contains repair instructions for when the vehicle sporadically does not start and there is a hard brake pedal concern. |
| A4621252054385_2 | 2021-03-04. Service bulletin. EQUIPMENT; SERVICE BRAKES. This informational contains an explanation for when the customer hears creaking noises when braking at almost standstill (crawling when pulling away or briefly before standstill). |
| SM 15-2021 | 2021-03-04. Service bulletin. EQUIPMENT. This special notice is to inform dealers to return the part numbers listed (State of California only). |
| AWA 21-01 | 2021-03-04. Service bulletin. EQUIPMENT:APPLIANCE:AIR CONDITIONER. This Document informs dealers on the new A/C evaporator warranty extension for 2017-2021 A4/S4/Q7 and 2018-2021 A5/S5/Q5 vehicles |
| A9721782061976_1 | 2021-03-04. Service bulletin. ELECTRICAL SYSTEM. This bulletin contains guidance for submitting warranty wiring repairs. |
| A9421342012749_1 | 2021-03-04. Service bulletin. EXTERIOR LIGHTING. This bulletin contains instructions for addressing condensation in the headlights. |
| A9121692062115_2 | 2021-03-04. Service bulletin. EQUIPMENT. This bulletin contains instructions for when the nav files are corrupted during an update. |
| A9121682062266_1 | 2021-03-04. Service bulletin. EQUIPMENT:ELECTRICAL:NAVIGATIONAL SYSTEM(GLOBAL POSITIONING SYSTEM). This bulletin states to create a PSS record when last destinations, favorites, and home/work addresses are sporadically lost. |
| A9121672061625_2 | 2021-03-04. Service bulletin. ELECTRICAL SYSTEM. This bulletin states to create a PSS record when the message "SOS - Emergency call malfunction, please contact service" is displayed in the instrument cluster and DTCs B129B11 and B239C11 are stored in the control module for emergency call module and communication unit. |
| A4621222051095_4 | 2021-03-04. Service bulletin. EQUIPMENT. This informational bulletin contains instructions on how to download and use the Audi Frequency App. |
| A1521372053278_6 | 2021-03-04. Service bulletin. ENGINE AND ENGINE COOLING. This bulletin contains repair instructions for 3.0 and 2.9 TFSI engines that have oil loss around the engine compartment, front end, and underbody. |
| A9421332061922_1 | 2021-03-04. Service bulletin. EQUIPMENT. This informational contains instruction on how to document optical concerns for warranty claims. |
| A9121652062115_1 | 2021-03-04. Service bulletin. ELECTRICAL SYSTEM. This bulletin contains instructions for when the nav files are corrupted during an update. |
| A462124203418118 | 2021-03-04. Service bulletin. SERVICE BRAKES. This technical service bulletin provides troubleshooting for brake noise. |
| A462123202258410 | 2021-03-04. Service bulletin. SERVICE BRAKES. This informational bulletin provides diagnostic information for brake conditions. |
| A4421802056386_4 | 2021-03-04. Service bulletin. STEERING. This bulletin contains instructions for when the vehicle pulls to one side or the steering wheel is crooked. |
| A7221322062113_1 | 2021-03-04. Service bulletin. SEATS. This bulletin contains instructions for when the second row backrests won't fold. |
| A6621692030471_6 | 2021-03-04. Service bulletin. EQUIPMENT. This informational bulletin covers the condition of when license plate mounting bracket threaded inserts are stripped. |
| A4421792022563_1 | 2021-03-04. Service bulletin. WHEELS. This bulletin provides information regarding vibrations or movement that are felt in the wheel. |
| A1721122060750_2 | 2021-03-04. Service bulletin. ENGINE AND ENGINE COOLING. This bulletin contains instructions for using the UV additive to find engine oil leaks. |
The summaries are NHTSA's. Each bulletin's page links NHTSA's copy of the manufacturer's document.