Audi · Known Issues
2021 Audi S5 Problems: 6 Known Issues
2021 model year · 497+ owner reports · Updated September 2026
2021 · All trims · All engines
Choose the year and equipment for your written issues and visual request.
2021 model year · 497+ owner reports · Updated September 2026
2021 · All trims · All engines
Choose the year and equipment for your written issues and visual request.
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According to Au7o's analysis of 497+ owner reports, the 2021 Audi S5 has 6 documented known issues, with 1 rated critical. The most serious is Rear Axle Trailing Arm Eccentric Bolt Lock Nut Fracture - Recall 21V295 (Audi 42L1) ($0-$0 repair). The most commonly reported issue is Thermostat and Water Pump Assembly Failure with 211 owner reports. Across all issues with published estimates, repair costs range from $300 to $1,200. DIY maintenance guides at au7o.io.
SEAT BELTS:FRONT:RETRACTOR
Volkswagen Group of America, Inc. (Volkswagen) is recalling certain 2025 GTI, Golf R, Audi A5, A6 Sportback E-Tron, S5, S6 Sportback E-Tron, 2026 Q4 Sportback E-Tron, and Q4 E-Tron vehicles. The torsion bar in one or both front seat belt retractors may have been damaged during production.
SEAT BELTS:REAR/OTHER:RETRACTOR
Volkswagen Group of America, Inc. (Audi) is recalling certain 2025 SQ6 E-Tron, SQ6 Sportback E-Tron, Q6 Sportback E-Tron, A6, A5, A6 Sportback E-Tron, Q6 E-Tron, S5, and S6 Sportback E-Tron vehicles. The automatic locking retractor may fail to engage when a child seat is installed using the seat belt. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard (FMVSS) numbers 208, "Occupant Crash Protection" and 209, "Seat Belt Assemblies."
BACK OVER PREVENTION: SENSING SYSTEM: CAMERA
Volkswagen Group of America, Inc. (Audi) is recalling certain 2021 Audi A8 and S8, 2022 Audi A5 Sportback, A4 Sedan, E-Tron GT, Q3, Q5, RS6 Avant, A3 Sedan, S5 Sportback, Q5 Sportback, Q7, Q8, RSQ8, SQ7, SQ8, and S3 Sedan vehicles. A software error may prevent the rear-view image from initially displaying when the vehicle begins to reverse. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard number 111, "Rear Visibility."
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According to Au7o's analysis of 497+ owner reports, the 2021 Audi S5 has 6 documented issues. The most frequently reported are: Rear Axle Trailing Arm Eccentric Bolt Lock Nut Fracture - Recall 21V295 (Audi 42L1), Thermostat and Water Pump Assembly Failure, 3.0T Supercharger Intercooler Pump Failure. Of these, 1 is rated critical and should be addressed promptly.
The 2021 Audi S5 has 6 known issues documented across 497+ owner reports. 1 issue is rated critical: Rear Axle Trailing Arm Eccentric Bolt Lock Nut Fracture - Recall 21V295 (Audi 42L1). Prospective buyers should inspect for these issues and factor potential repair costs into their purchase decision. Regular maintenance following the manufacturer's schedule helps prevent many common problems.
Repair costs for known Audi S5 issues range from $0 to $1,200, depending on the specific problem and whether you choose DIY or professional repair. The most critical issue, Rear Axle Trailing Arm Eccentric Bolt Lock Nut Fracture - Recall 21V295 (Audi 42L1), typically costs $0-$0 to repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.
Lock nuts from specific production batches used on the eccentric alignment bolt at the rear trailing arm are prone to stress corrosion cracking. If the nut fractures, the eccentric bolt can rotate and the rear wheel alignment changes on its own, producing sudden instability and a… Repairs typically run $0-$0. Severity: high.
The S5 3.0T thermostat and water pump assembly uses a plastic housing that degrades over time. Leaks develop at the housing seams and O-ring seals, often around 60,000-80,000 miles. Repairs typically run $400-$1,000. Severity: medium.
Content on this page was compiled with AI assistance using NHTSA complaints, TSBs, owner reports, and public automotive data. While we strive for accuracy, this information may contain errors. Always verify repair procedures and specifications with your vehicle's service manual or a qualified mechanic.
EQUIPMENT:ELECTRICAL:INFOTAINMENT:VIDEO (TOUCH)SCREEN/MONITOR/UNIT
Volkswagen Group of America, Inc. (Audi) is recalling certain 2021-2022 AUDI A8, A6 Allroad, E-TRON Quattro, 2022 S3, RSQ8, RS7, RS6 Avant, Q8, Q7, Q3, E-TRON Sportback Quattro, S5 Cabriolet, E-TRON GT, S5 Sportback, A7, A6, A5 Sportback, A5 Cabriolet, A4, A4 Allroad, A3, S8, SQ7, SQ8, S6, and S4 vehicles. The infotainment main unit may become damaged internally when the vehicle is shut off, resulting in an inoperative rearview camera display the next time the vehicle is started. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard number 111, "Rear Visibility."
AIR BAGS:SENSOR:OCCUPANT CLASSIFICATION:FRONT PASSENGER
Volkswagen Group of America, Inc. (Volkswagen) is recalling certain 2023 Audi S5 Cabriolet, A4 Allroad, Q5 Sportback, A3 Sedan, S5 Sportback, SQ7, TT Coupe, TT Roadster, RS5 Sportback, 2024 A8, E-Tron Quattro, E-Tron Sportback Quattro, Q8, RSQ8, 2023-2024 Q3, Q5, and Q7 vehicles. An electrical connection in the front passenger seat for the occupant detection system (ODS) control module may loosen and deactivate the front passenger air bag.
+ 5 more recalls. Check all on NHTSA.gov
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The water-to-air intercooler system on the S5 3.0T uses an electric coolant pump that can fail, causing elevated charge air temperatures and reduced power. Heat soak becomes severe in warm climates. Repairs typically run $300-$700. Severity: medium.
The S5 suffers from carbon deposit accumulation on intake valves common to all Audi direct-injected engines. The performance-oriented tuning makes power loss from carbon more noticeable than in base models. Repairs typically run $400-$900. Severity: medium.
Late B9 S5 models were subject to two separate rearview camera recalls in 2022. In one, a software fault leaves the camera image blank when reverse is selected; in the other, the display fails to show the camera image after the vehicle has been shut down and restarted. Either con… Repairs typically run $0-$0. Severity: medium.
On the B9 3.0 TFSI the crankcase pressure regulator (PCV) is integrated into the valve cover. The rubber diaphragm tears, opening a large unmetered vacuum leak into the intake. The signature is a loud whistle under the hood at idle that stops instantly when the oil filler cap is… Repairs typically run $450-$1,200. Severity: medium.