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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

Bulletins, newest first
A0021482021205_62021-07-02. Service bulletin. EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL; STRUCTURE. This informational bulletin explains how to order replacement VIN plates, Safety Certification Labels, etc.
A1521392053278_82021-07-02. Service bulletin. ENGINE AND ENGINE COOLING:ENGINE:OIL/LUBRICATION. 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.
A9121102062115_52021-07-02. 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_12021-07-02. Service bulletin. ELECTRICAL SYSTEM; EQUIPMENT; EQUIPMENT ADAPTIVE/MOBILITY. This bulletin states to create a PSS when the MMI display turns blue. Workaround provided.
A0021472031473_32021-07-02. 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_12021-07-02. 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_12021-07-02. Service bulletin. EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL; ELECTRICAL SYSTEM. This bulletin contains instructions for troubleshooting FoD malfunctions.
A4821052063527_12021-07-02. Service bulletin. STEERING; EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL. This bulletin contains instructions for calibrating the steering angel sender G85.
A4821042063528_12021-07-02. Service bulletin. ENGINE; EQUIPMENT. This bulletin contains instructions for addressing intermediate shaft noises that are heard in the engine compartment.
A4821032063546_12021-07-02. Service bulletin. EQUIPMENT; STEERING. This bulletin states how to check for a dynamic steering actuator problem. Solution is under development.
A4821022061904_32021-07-02. 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.
A4321482059665_22021-07-02. Service bulletin. SUSPENSION; ELECTRICAL SYSTEM:SOFTWARE. This bulletin contains a software update that corrects the control module configuration and addresses a warning light.
A4321472051336_42021-07-02. Service bulletin. EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL. This bulletin contains repair instructions for DTC B200FF0.
21TechRefGde5262021-06-03. Service bulletin. BACK OVER PREVENTION; TIRES:PRESSURE MONITORING AND REGULATING SYSTEMS; EQUIPMENT:ELECTRICAL:NAVIGATIONAL SYSTEM(GLOBAL POSITIONING SYSTEM). All models except Q3, R8, and TT: Settings Section: Split Verify and set language & measurements checklist items into 2 separate with instructions. Changed instructions for "Set Entertainment Fad in Parking aid", " Set Music volune while parking to Medium", and "Turn off Manual Seed Warning". Media/Radio/Sat Section: Changed instructions for "Verify HD Radio is turned "off". On-Hoist Inspection Section: Changed where to store tire pressures for Set and store tirepressures" to "Home > Vehicle > Settings & Service > Tire pressure monitoring". Audi connect Section: Changed instructions for "Turn on the Wi-Fi hotspot", Check Wi-Fi hotspot visibility", and Enable satellite map view for navigation"
A9121052061933_22021-06-03. Service bulletin. ELECTRICAL SYSTEM: INSTRUMENT CLUSTER/PANEL; EQUIPMENT:ELECTRICAL:NAVIGATIONAL SYSTEM(GLOBAL POSITIONING SYSTEM). This bulletin contains an explanation and troubleshooting for the Navigation messages in the instrument cluster.
A1321142061461_32021-06-03. Service bulletin. ELECTRICAL SYSTEM:ALTERNATOR/GENERATOR/REGULATOR:INTEGRATED STARTER(OTHER THAN PROPULSION); POWER TRAIN:DRIVELINE:CHAIN/BELT. This bulletin contains repair instructions to address noises or a message in the DIS display.
A9121042024323_82021-06-03. Service bulletin. EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL; ELECTRICAL SYSTEM:ADAS:PARKING ASSIST:SOFTWARE. This bulletin contains technical information regarding when the parking aid sporadically warns of obstacles that don't exist or it is inoperative/constant warning.
A6921662063398_12021-06-03. Service bulletin. SEAT BELTS. This informational bulletin outlines what is damage due to outside influence on a seat belt.
SM 39-20212021-06-03. Service bulletin. EQUIPMENT. This special notice is to inform dealers to return the parts listed and only order the successor parts going forward
A9021032058077_52021-06-03. Service bulletin. EQUIPMENT; SERVICE BRAKES. This bulletin contains instructions for determining unexpected Audi presense interventions.
A1021222018288_92021-06-03. Service bulletin. EQUIPMENT; ENGINE AND ENGINE COOLING. This technical service bulletin reminds the reader to check for metal debris when replacing an engine.
A0021442052680_32021-06-03. Service bulletin. EQUIPMENT. This bulletin contains instructions for additional reporting requirements for safety related inquiries (airbag/seatbelts, accidents, fire and overheat damage).
SM 37-20212021-06-03. Service bulletin. EQUIPMENT. This special notice is to inform dealers to return the parts listed if it meets the criteria provided.
A9121002061028_22021-06-03. Service bulletin. VISIBILITY. This bulletin explains and troubleshoots when Audi connect does not have a green SOS light.
A8721132010146_12021-06-03. Service bulletin. STRUCTURE. This bulletin contains instructions for properly cleaning and removing a musty odor in the vehicle.

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