WenmarOpen by Wenmar Pro

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
SM 05-20212021-02-04. Service bulletin. EQUIPMENT. This special notice is to inform dealers to return the parts listed if it meets the criteria provided.
A9121642024323_72021-02-04. Service bulletin. PARKING BRAKE:ELECTRICAL:CONTROL MODULE. This bulletin contains technical information regarding when the parking aid sporadically warns of obstacles that don't exist or it is inoperative/constant warning.
A9121622061934_12021-02-04. Service bulletin. EQUIPMENT. This bulletin states to ignore DTCs U156C00, B1A06F1, B1A06F2 and to not perform any repairs or run any test plans for these ghost DTCs.
A1921112061918_12021-02-04. Service bulletin. ENGINE AND ENGINE COOLING. This bulletin provides guidance on diagnosing a coolant light concern with normal coolant level in the tank.
A1521362053278_52021-02-04. 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.
A7221312060085_42021-02-04. Service bulletin. SEATS; ELECTRICAL SYSTEM:SOFTWARE. This bulletin contains a software update that addresses the sporadic issue where the front seats move into an implausible position.
A6621682046229_22021-02-04. Service bulletin. STRUCTURE. This informational bulletin outlines proper warranty procedure for optical defects.
A4821922061904_12021-02-04. Service bulletin. EQUIPMENT; EQUIPMENT ADAPTIVE/MOBILITY; ELECTRICAL SYSTEM. This bulletin contains repair instruction for when DTC C110DF0 is stored and the yellow steering lamp is on.
A0121962060429_22021-02-04. Service bulletin. ENGINE AND ENGINE COOLING; EQUIPMENT; EQUIPMENT ADAPTIVE/MOBILITY. This bulletin contains instructions for when there may be a noise from the exhaust flap or there are DTCs sporadically stored in the ECM.
A9120432061625_12021-01-08. Service bulletin. EQUIPMENT ADAPTIVE/MOBILITY; EQUIPMENT:ELECTRICAL. SOS emergency call malfunction, DTC B129B11 and B129C11 are stored in the emergency call control module
A7220302060085_32021-01-08. Service bulletin. ELECTRICAL SYSTEM:SOFTWARE; SEATS. This bulletin contains a software update that addresses the sporadic issue where the front seats move into an implausible position.
A5320042043016_22021-01-08. Service bulletin. ELECTRICAL SYSTEM:PROPULSION SYSTEM: CABLES; EQUIPMENT. This bulletin contains repair instructions for when cables are hanging in view with no DTCs.
A5520512014055_82021-01-08. Service bulletin. EQUIPMENT; ENGINE; EQUIPMENT ADAPTIVE/MOBILITY. This bulletin contains instructions for addressing discoloration due to moisture on a new vehicle.
A3920382060169_22021-01-08. Service bulletin. ELECTRICAL SYSTEM. This bulletin contains instructions for when DTC U101300 is logged with sports differential warning lamps or messages.
A3420502061714_12021-01-08. Service bulletin. POWER TRAIN. This bulletin contains repair instructions for resolving a leak on the transmission case.
A0020432061669_12021-01-08. Service bulletin. ELECTRICAL SYSTEM; EQUIPMENT; EQUIPMENT ADAPTIVE/MOBILITY. This informational bulletin contains instructions for Audi connect before performing any MMI work.
21A4S4ALRDCSDEL2021-01-08. Service bulletin. ELECTRICAL SYSTEM. Infotainment Section: ADDED: Check radio settings and ensure 'Online additional data' is toggled on and 'online station tracking' is set to Automatic
SM C-20202021-01-08. Service bulletin. EQUIPMENT. This special notice is to inform dealers to return the part numbers listed (State of California only).
A0020362002047_12020-12-21. Service bulletin. EQUIPMENT:ELECTRICAL. This information bulletin contains instructions for technicans on how to ensure their TAC call goes smoothly.
A9120392061490_12020-12-04. Service bulletin. ENGINE AND ENGINE COOLING:ENGINE:OIL/LUBRICATION. This bulletin covers Audi connect: oil level in the myAudi app is implausible
A9120362061345_12020-12-04. Service bulletin. ELECTRICAL SYSTEM; EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL. This informational bulletin contains information regarding connectivity issues.
A4620192061331_12020-12-04. Service bulletin. SERVICE BRAKES, AIR:ANTILOCK:ABS WARNING LIGHT; EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL. This bulletin contains instructions for addressing an ABS warning light with DTCs C050200 and/or C050800.
A4620182061403_12020-12-04. Service bulletin. SERVICE BRAKES, AIR:DISC:PADS; EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL. This bulletin contains instructions for addressing a brake pad wear indicator light with no DTCs.
A9120272061257_12020-12-04. Service bulletin. ELECTRICAL SYSTEM:SOFTWARE. This bulletin contains instructions regarding Audi connect software failures and how to resolve it.
2010-2021EngOil2020-12-04. Service bulletin. EQUIPMENT. Added Saga Part number for 0W40 oil: SAGA Part: G E55040S0

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