2021 Audi S4: common problems and reliability
· B9One of the better S4 years.
2 owner complaints, most about electrical system. 4 recalls.
Should I buy a 2021 S4?The 2021 Audi S4 has 2 owner-filed NHTSA complaints and 4 recalls on record. The most-reported areas are electrical system. Owners most often flag catastrophic engine failure with low compression or cylinder 6 damage, often on tuned cars.
Safety record for the 2021 model year
Source: NHTSA complaints and recalls filed for 2021 Audi S4 vehicles (US, public record).
The Year Score compares this year with other S4 years only. How we score it
Is 2021 a good year for the S4?
Across the 18 S4 model years we track, complaint volume runs from 1 (2022) to 148 (2000). With 2 complaints, the 2021 S4 sits below the model's median of 22.
These are raw NHTSA complaint totals, not adjusted for how many cars sold or how long each model year has been on the road. Older and higher-selling years accumulate more complaints.
Where owners report problems
Recalls affecting the 2021 S4
seat belts:rear/other:retractor
Campaign 21V606000Volkswagen Group of America, Inc. (Volkswagen) is recalling certain 2021 Volkswagen ID4, Audi A4 Allroad, A4 Sedan, A5 Cabriolet, A5 Coupe, A5 Sportback, A6 Allroad, A6 Sedan, A7, A8, E-Tron Quattro, E-Tron Sportback Quattro, Q3, Q5, Q5 Sportback, Q7, Q8, RS5 Sportback, RS5 Coupe, RS6 Avant, RS7, RSQ8, S4 Sedan, S5 Cabriolet, S5 Coupe, S5 Sportback, S6 Sedan, S7, S8, SQ5, SQ5 Sportback, SQ7, SQ8, and 2021-2022 S3 Sedan vehicles. The rear seat belt automatic locking retractors may deactivate early, which can prevent the child restraint system from securing properly. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard number 208, "Occupant Crash Protection."
tires
Campaign 22V034000Volkswagen Group of America, Inc. (Audi) is recalling certain 2019-2021 Audi A5 Sportback, RS5 Coupe, RS5 Sportback, S5 Sportback, 2020-2021 A4 Allroad, A4 Sedan, A5 Cabriolet, A5 Coupe, A6 Allroad, A6 Sedan, A7, A8, Q5, S4 Sedan, S5 Coupe, S5 Cabriolet, S6 Sedan, S7, S8, SQ5, 2021 Q5 Sportback, Q7, Q8, RS6 Avant, RS7, RSQ8, SQ5 Sportback, SQ7, and SQ8 vehicles. The rear axle alignment may not have been inspected after the repairs for Recall 21V-295 (42L1) were performed.
suspension:rear:axle:non-powered axle assembly
Campaign 21V295000Volkswagen Group of America, Inc. (Audi) is recalling certain 2021 Q7, Q8, Q5 Sportback, SQ5 Sportback, RS6 Avant, RS7, RS Q8, 2020-2021 Audi S6 sedan, Q5, A8, S8, A7, A6 Allroad, A5 Cabriolet, A4 sedan, A4 Allroad, SQ5, S7, A6 sedan, S5 coupe, S4 sedan, S5 Cabriolet, A5 coupe, 2019-2021 RS5 coupe, A5 Sportback, S5 Sportback, RS5 Sportback vehicles. The lock nut on the trailing arm of the rear axle may break due to stress corrosion.
back over prevention:display function
Campaign 22V742000Volkswagen Group of America, Inc. (Volkswagen) is recalling certain 2021 Audi A8, RS7, RS6 Avant, RS5 Sportback, RS5 Coupe, Q8, Q7, Q5 Sportback, S4 Sedan, Q5, A7, A6, A6 Allroad, A5 Sportback, A5 Coupe, A5 Cabrioleet, A4 Sedan, A4 Allroad, E-Tron Sportback Quattro, SQ7, S5 Cabriolet, E-Tron Quattro, SQ8, SQ5 Sportback, SQ5, S8, S7, S6 Sedan, S5 Sportback, S5 Coupe, 2022 E-Tron GT, and 2021-2022 RSQ8 vehicles. Due to a software issue, a blank or black screen may be displayed instead of the rearview camera image when the vehicle is placed in reverse gear. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard number 111, "Rear Visibility."
What owners report on the B9 S4
Owners of the B9 S4 generally describe it as a well-built, fun-to-drive, and solid car when properly maintained, with praise for its design, dynamic mode, and the strong low-RPM torque of the 3.0T engine.
- Very frequentRocker arm wear leading to engine failure, particularly on 2018 and early 2019 cars
- Very frequentCatastrophic engine failure with low compression or cylinder 6 damage, often on tuned cars
- RecurrentWater pump and thermostat failure, sometimes sending coolant into the vacuum system
- RecurrentPCV valve failure
- RecurrentCarbon buildup
Owner insights for the B9 S4. Read the full B9 owner report.
Typical used price
Used S4 listings typically run $18,495–$33,900 across 2010 to 2023 model years.
Other S4 model years
Compare every S4 year side by side to see how 2021 ranks against the rest.
Compare the S4 against its rivals
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