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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
A4421842065160_12021-12-07. Service bulletin. EQUIPMENT; EQUIPMENT ADAPTIVE/MOBILITY; TIRES:TEMPORARY/EMERGENCY SPARE TIRE. This informational bulletin explains how the temporary/collapsible spare wheel inflates.
A9121502062115_72021-12-07. Service bulletin. ELECTRICAL SYSTEM:SOFTWARE. This bulletin contains instructions for when the nav files are corrupted during an update.
A3921452048671_52021-12-07. Service bulletin. ELECTRICAL SYSTEM: INSTRUMENT CLUSTER/PANEL. This bulletin contains instructions for when DTC U030000 appears and “All Wheel Drive Malfunction Message” is displayed in the instrument cluster.
A9021222064983_12021-12-07. Service bulletin. ELECTRICAL SYSTEM: INSTRUMENT CLUSTER/PANEL. This bulletin states to replace the instrument cluster when there is a colorful vertical line (pixel error) in the Audi virtual cockpit.
A5721862058452_32021-12-07. Service bulletin. VISIBILITY:DEFROSTER/DEFOGGER/HVAC SYSTEM:REAR WINDOW. This bulletin contains repair instructions for when the rear window defog button will light up and then turn off.
A4821132063528_22021-12-07. Service bulletin. ENGINE. This bulletin contains instructions for addressing intermediate shaft noises that are heard in the engine compartment.
A9121472061625_32021-12-07. Service bulletin. ELECTRICAL SYSTEM: INSTRUMENT CLUSTER/PANEL. 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.
A9121462063702_32021-11-05. Service bulletin. UNKNOWN OR OTHER. This bulletin states to create a PSS when the MMI display turns blue. Workaround provided.
A9121442062942_32021-11-05. Service bulletin. UNKNOWN OR OTHER. This bulletin states to create a PSS record when the detailed interaction map flickers.
A9121422062266_32021-11-05. Service bulletin. UNKNOWN OR OTHER. This bulletin states to create a PSS record when last destinations, favorites, and home/work addresses are sporadically lost.
A9121412064818_12021-11-05. Service bulletin. EQUIPMENT:ELECTRICAL:INFOTAINMENT:BLUETOOTH/WIFI; UNKNOWN OR OTHER. This bulletin contains repair instructions for when it is not possible to establish a bluetooth connection with DTC U110300.
A9121402063702_22021-11-05. Service bulletin. SERVICE BRAKES, ELECTRIC:SOFTWARE/PROGRAMMING; FORWARD COLLISION AVOIDANCE: CRASH IMMINENT BRAKING. This bulletin states to create a PSS when the MMI display turns blue. Workaround provided.
A9021162063913_32021-11-05. Service bulletin. ELECTRICAL SYSTEM: INSTRUMENT CLUSTER/PANEL. This bulletin contains a software update for when the cluster's driver information system is blank.
A6921722063398_22021-11-05. Service bulletin. UNKNOWN OR OTHER. This informational bulletin outlines what is damage due to outside influence on a seat belt.
A3521392064312_12021-11-05. Service bulletin. POWER TRAIN. This bulletin contains three different repair scenarios for when DTC P17F900 is stored in the TCM with symptom code 22345 and there is a gearbox malfunction message.
A3421532064848_12021-11-05. Service bulletin. POWER TRAIN. This bulletin addresses an issue where basic settings cannot be performed as DTC P17F900 is stored in the TCM.
A0121142063394_22021-11-05. Service bulletin. ENGINE AND ENGINE COOLING. This bulletin contains instructions for clearing DTCs P023600 and P060600.
A9121382064681_12021-11-05. Service bulletin. EQUIPMENT. Informational TSB detailing why the mobile device sometimes cannot be charged wirelessly.
A7221372064695_12021-11-05. Service bulletin. STRUCTURE; SEATS. The informational bulletin explains the technical aspect of enter/exit assistance.
DC 202109282021-10-06. Service bulletin. EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL. Dealer Communication - Vehicle Sales Reporting, Reinstatement, and Audit Policy Update - Effective September 30, 2021
SM 70-20212021-10-06. Service bulletin. ELECTRICAL SYSTEM; EQUIPMENT. This special notice is to inform dealers to return the parts listed if it meets the criteria provided.
A9121342018187_12021-10-05. Service bulletin. EQUIPMENT. This bulletin contains inspection guidelines for radio interference that causes noises in the speaker.
A9121332064292_12021-10-05. 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_32021-10-05. Service bulletin. ELECTRICAL SYSTEM; EQUIPMENT. This bulletin explains and troubleshoots when Audi connect does not have a green SOS light.
A9121302062115_62021-10-05. Service bulletin. EQUIPMENT:ELECTRICAL. This bulletin contains instructions for when the nav files are corrupted during an update.

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