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Service bulletins for the 2020 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.

1073 on file from NHTSA, as of 2026-10-19.

By type

By component

By trouble code

By topic

Bulletins, newest first
A5721752022032_92021-05-06. Service bulletin. LATCHES/LOCKS/LINKAGES; ELECTRICAL SYSTEM. This technical service bulletin provides troubleshooting information for the vehicle locking system.
A5521542062730_12021-05-06. Service bulletin. EQUIPMENT. This bulletin explains why the compartment lid cannot be closed using the buttons on the key sometimes.
A1521382053278_72021-05-06. Service bulletin. ENGINE. 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.
A9121862062713_12021-04-06. Service bulletin. EQUIPMENT. This bulletin contains repair instructions for when there is radio static when the rear heater is active.
A9121832060522_22021-04-06. Service bulletin. ELECTRICAL SYSTEM. This bulletin contains a software update that corrects audio output issues and only one or station or less in the station list.
A5521532062669_12021-04-06. Service bulletin. ENGINE AND ENGINE COOLING. This bulletin states that this is a normal condition and to not perform any repairs.
A9421362023322_32021-04-06. Service bulletin. EXTERIOR LIGHTING. This informational bulletin contains information on the different shading of LED headlights.
A8021112062583_12021-04-06. Service bulletin. EQUIPMENT. This bulletin contains instructions for addressing an insufficient or uneven heating performance from the HVAC system.
A5021062062633_12021-04-06. Service bulletin. STRUCTURE. This bulletin contains instructions for when there is a creaking noise in the floor area while strongly braking or steering where the vehicle's body is twisted.
A9121822062115_32021-04-06. Service bulletin. ELECTRICAL SYSTEM. This bulletin contains instructions for when the nav files are corrupted during an update.
A4821962055733_22021-04-06. Service bulletin. STEERING. This bulletin contains repair instructions for repositioning the intermediate steering shaft when there is squeaking noises from the steering column.
A1321132062387_12021-04-06. Service bulletin. ENGINE AND ENGINE COOLING. This bulletin contains instructions for determining if a repair is needed when coolant touches a poly V-belt and/or a toothed belt.
SM 17-20212021-04-06. Service bulletin. ELECTRICAL SYSTEM. This special notice is to inform dealers to return the parts listed if it meets the criteria provided.
A9121792062480_12021-04-06. Service bulletin. ELECTRICAL SYSTEM. This bulletin states to clear the DTCs and release the vehicle.
A9121782050565_32021-04-06. Service bulletin. ELECTRICAL SYSTEM. This bulletin contains general software update instructions for vehicles with PR Code 7UH.
A9121762037809_82021-04-06. Service bulletin. EQUIPMENT. This informational bulletin contains instructions about updating the navigation map.
A1921122061918_22021-04-06. Service bulletin. ENGINE AND ENGINE COOLING. This bulletin provides guidance on diagnosing a coolant light concern with normal coolant level in the tank.
A5721742058452_22021-03-04. Service bulletin. VISIBILITY. This bulletin contains repair instructions for when the rear window defog button will light up and then turn off.
A3921402059057_32021-03-04. Service bulletin. WHEELS; SUSPENSION. This bulletin contains repair instructions for noises when in reverse or vibrations/humming/droning or rubbing when fully turning the wheel.
A4721082055646_22021-03-04. 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_22021-03-04. 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 15-20212021-03-04. Service bulletin. EQUIPMENT. This special notice is to inform dealers to return the part numbers listed (State of California only).
AWA 21-012021-03-04. 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_12021-03-04. Service bulletin. ELECTRICAL SYSTEM. This bulletin contains guidance for submitting warranty wiring repairs.
A9421342012749_12021-03-04. Service bulletin. EXTERIOR LIGHTING. This bulletin contains instructions for addressing condensation in the headlights.

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