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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

Only bulletins with component: Equipment and accessories are shown. Show all

Bulletins, newest first
2010-2021EngOil2020-12-04. Service bulletin. EQUIPMENT. Added Saga Part number for 0W40 oil: SAGA Part: G E55040S0
21A4S4TECHREP2020-11-05. Service bulletin. EQUIPMENT; ELECTRICAL SYSTEM. Driver Assistance Section: ADDED: "Activate rear cross traffic assist (if equipped)"
A9120242026611_72020-11-05. Service bulletin. ELECTRICAL SYSTEM; EQUIPMENT. This bulletin contains a guide for troubleshooting HD radio issues.
A9120202061028_12020-11-05. Service bulletin. ELECTRICAL SYSTEM; EQUIPMENT; EQUIPMENT ADAPTIVE/MOBILITY. This bulletin explains and troubleshoots when Audi connect does not have a green SOS light.
A5020012060825_12020-11-05. Service bulletin. EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL; EQUIPMENT ADAPTIVE/MOBILITY. This informational bulletin explains a technical change to the vehicle.
A9020732059891_32020-11-05. Service bulletin. EQUIPMENT; ELECTRICAL SYSTEM. This informational bulletin directs you to read the SSP and not perform any repairs for the concern.
A1720112060750_12020-11-05. Service bulletin. ENGINE AND ENGINE COOLING:ENGINE:OIL/LUBRICATION; EQUIPMENT. This bulletin contains instructions for using the UV additive to find engine oil leaks.
A0020422045316_52020-11-05. Service bulletin. EQUIPMENT ADAPTIVE/MOBILITY; ENGINE AND ENGINE COOLING:ENGINE. This bulletin contains information for diagnosing the Start/Stop system.
21AUUSMaint09202020-10-06. Service bulletin. EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL. New Document
21AUTIRECHAINS2020-10-06. Service bulletin. TIRES; EQUIPMENT; WHEELS. Added new graphic to reflect where to find MY 21 information
A9120142060675_12020-10-06. Service bulletin. STRUCTURE; ELECTRICAL SYSTEM:ADAS:PARKING ASSIST:WARNING; ELECTRICAL SYSTEM:ADAS:PARKING ASSIST:SENSORS; EQUIPMENT:ELECTRICAL. This bulletin contains instructions for addressing the issue when the parking assist will intermittently alert the customer to an obstruction and the sensors look 'pushed in'.
A9120112037809_72020-10-06. Service bulletin. EQUIPMENT:ELECTRICAL:NAVIGATIONAL SYSTEM(GLOBAL POSITIONING SYSTEM). This informational bulletin contains instructions about updating the navigation map.
21A4S4TECHREP2020-10-06. Service bulletin. EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL. Vehicle Preparation Section: ADDED: "FCC ID, and Model" to" Verify Audi phone box customer registration form is present in vehicle and add the serial number, FCC ID, and Model from Elsa (if equipped). See TSB 2051720" Media / Radio / SAT Section: ADDED: "Confirm SiriusXM is on and in an active state (can scroll through channels and hear music)" ADDED Phone Box Form to the end of the document
21A4S4ALRDCSDEL2020-10-06. Service bulletin. EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL. Infotainment Section: ADDED: - Tune to SiriusXM and show SiriusXM presets and customize based on customers listening preferences - Show differences of SAT vs IP channels through the On Demand category in SiriusXM with 360L equipped vehicles
A9020652032113_42020-09-03. Service bulletin. EQUIPMENT; ENGINE AND ENGINE COOLING:COOLING SYSTEM. This information bulletin contains a background on the outside air temperature reading.
A0120832060429_12020-09-03. Service bulletin. EQUIPMENT; ENGINE AND ENGINE COOLING:EXHAUST SYSTEM. This bulletin contains instructions for when there may be a noise from the exhaust flap or there are DTCs sporadically stored in the ECM.
A6920562059223_22020-09-03. Service bulletin. ELECTRICAL SYSTEM; EQUIPMENT. This bulletin contains information regarding the replacement of PODs components.
2010-2021EngOil2020-09-03. Service bulletin. ENGINE; EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL. New document
Audi Part Labels2020-09-03. Service bulletin. EQUIPMENT. Recall Reminder Part Labels
A4020132059474_22020-08-06. Service bulletin. SUSPENSION:FRONT:SHOCK ABSORBER; EQUIPMENT. This bulletin contains instructions for correcting buffer stop noise (rumbling or squeaking from the front end).
A9120842060194_12020-08-06. Service bulletin. EQUIPMENT; ELECTRICAL SYSTEM:SOFTWARE; ELECTRICAL SYSTEM:INSTRUMENT PANEL:FUEL GAUGE:FUEL LEVEL FLOAT/SENSOR/SENDING UNIT. This bulletin states to create a PSS for when the Gas pop-up is blank.
21VEHCONDREP7132020-08-06. Service bulletin. EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL. New Document
21TIREPRSTBL062020-08-06. Service bulletin. EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL; TIRES:PRESSURE MONITORING AND REGULATING SYSTEMS. New Document
21TechRefGde6302020-08-06. Service bulletin. EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL. New Document
21DETAILREPT7132020-08-06. Service bulletin. EQUIPMENT. New Document

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