Service bulletins for the 2021 Audi S4
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.
969 on file from NHTSA, as of 2026-10-19.
By type
By component
By trouble code
Only bulletins with component: Engine are shown. Show all
| A192336202530314 | 2023-04-06. Service bulletin. ENGINE AND ENGINE COOLING. This bulletin provides information on the discontinuation and mixing of Audi-approved engine coolants. |
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| A3923512060424_3 | 2023-03-06. Service bulletin. ENGINE AND ENGINE COOLING. This bulletin provides instructions for when there is an oil leak from the rear of the vehicle and is confirmed from the top of the differential near the output flanges. One or both of the sealing caps are missing from the pressure-limiting valves. |
| A8722302067716_1 | 2022-09-01. Service bulletin. ENGINE AND ENGINE COOLING; EQUIPMENT. This bulletin advises that techs should document the specific o-ring seal that is replaced if a refrigerant leak is found and caused by the o-ring seal. |
| A3922472064024_2 | 2022-05-05. Service bulletin. ENGINE. This bulletin contains repair instructions for when there is an oil leak from the rear of the vehicle and the sealing caps are missing from the pressure limiting valves. |
| A4822282063528_3 | 2022-05-05. Service bulletin. ENGINE AND ENGINE COOLING. This bulletin contains instructions for addressing intermediate shaft noises that are heard in the engine compartment. |
| A8722242064077_1 | 2022-05-05. Service bulletin. ENGINE AND ENGINE COOLING. This TSB describes a method for leak detection for R134A and R1234yf refrigerant platforms only. |
| A1722172060750_3 | 2022-04-05. Service bulletin. ENGINE AND ENGINE COOLING. This bulletin contains instructions for using the UV additive to find engine oil leaks. |
| A9222282065963_1 | 2022-03-04. Service bulletin. ENGINE AND ENGINE COOLING:COOLING SYSTEM:HOSES/LINES/PIPING/FITTINGS. This bulletin describes various conditions that may have arisen due to a leak in the corrugated windshield washer hose, and the associated repair. |
| A192228202530313 | 2022-02-04. Service bulletin. ENGINE AND ENGINE COOLING; EQUIPMENT. This bulletin contains instructions for identifying and mixing factory fill coolants. |
| A192227202530312 | 2022-02-04. Service bulletin. ENGINE AND ENGINE COOLING:COOLING SYSTEM; EQUIPMENT. This bulletin contains instructions for identifying and mixing factory fill coolants. |
| A1921262061918_4 | 2022-01-05. Service bulletin. ENGINE AND ENGINE COOLING:COOLING SYSTEM; EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL. This bulletin provides guidance on diagnosing a coolant light concern with normal coolant level in the tank. |
| A4821132063528_2 | 2021-12-07. Service bulletin. ENGINE. This bulletin contains instructions for addressing intermediate shaft noises that are heard in the engine compartment. |
| A1921222046712_3 | 2021-08-04. Service bulletin. ENGINE AND ENGINE COOLING; EQUIPMENT; FUEL SYSTEM, GASOLINE:STORAGE:TANK ASSEMBLY:FILLER PIPE AND CAP. This informational bulletin contains guidelines for figuring out why coolant marks are present around the coolant expansion tank cap. |
| A1921192061918_3 | 2021-07-02. Service bulletin. ENGINE AND ENGINE COOLING; EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL. This bulletin provides guidance on diagnosing a coolant light concern with normal coolant level in the tank. |
| A4821042063528_1 | 2021-07-02. Service bulletin. ENGINE; EQUIPMENT. This bulletin contains instructions for addressing intermediate shaft noises that are heard in the engine compartment. |
| A1021222018288_9 | 2021-06-03. Service bulletin. EQUIPMENT; ENGINE AND ENGINE COOLING. This technical service bulletin reminds the reader to check for metal debris when replacing an engine. |
| A5521532062669_1 | 2021-04-06. Service bulletin. ENGINE AND ENGINE COOLING. This bulletin states that this is a normal condition and to not perform any repairs. |
| A0121012054893_5 | 2021-04-06. Service bulletin. ENGINE AND ENGINE COOLING. This bulletin contains instructions for documenting the "Please reduce Oil Level" message in the instrument cluster potentially with an Engine Warmup request. |
| A1321132062387_1 | 2021-04-06. 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. |
| 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. |
| 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. |
| A1921112061918_1 | 2021-02-04. Service bulletin. ENGINE AND ENGINE COOLING. This bulletin provides guidance on diagnosing a coolant light concern with normal coolant level in the tank. |
| A0121962060429_2 | 2021-02-04. 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. |
| A5520512014055_8 | 2021-01-08. Service bulletin. EQUIPMENT; ENGINE; EQUIPMENT ADAPTIVE/MOBILITY. This bulletin contains instructions for addressing discoloration due to moisture on a new vehicle. |
| A9120392061490_1 | 2020-12-04. Service bulletin. ENGINE AND ENGINE COOLING:ENGINE:OIL/LUBRICATION. This bulletin covers Audi connect: oil level in the myAudi app is implausible |
The summaries are NHTSA's. Each bulletin's page links NHTSA's copy of the manufacturer's document.