2018 Audi S4 Problems: 2 Known Issues
2018 model year · NHTSA recalls, manufacturer TSBs, and owner forum reports · Updated October 2026
According to Au7o's research across NHTSA recalls, manufacturer TSBs, and owner forum reports, the 2018 Audi S4 has 2 documented known issues, with 2 rated critical. The most serious are EA839 3.0T Water Pump Internal Seal Failure Leaks Coolant Into the Vacuum System (Class Action) ($1,200-$3,000 repair) and Seat-Heater Cable Contact Fault Disables the Passenger Airbag (Recall 21V874 / 74E3) ($0-$0 repair). Across all issues with published estimates, repair costs range from $1,200 to $3,000. DIY maintenance guides at au7o.io.
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All 2 Known Issues
NHTSA Recalls5 recalls
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."
SEAT BELTS:REAR/OTHER:RETRACTOR
Volkswagen 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
Volkswagen 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
Volkswagen 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
Volkswagen 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."
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Frequently Asked Questions
What are the most common Audi S4 problems?
According to Au7o's research across NHTSA recalls, manufacturer TSBs, and owner forum reports, the 2018 Audi S4 has 2 documented issues. The most frequently reported are: EA839 3.0T Water Pump Internal Seal Failure Leaks Coolant Into the Vacuum System (Class Action), Seat-Heater Cable Contact Fault Disables the Passenger Airbag (Recall 21V874 / 74E3). Of these, 2 are rated critical and should be addressed promptly.
Is the Audi S4 reliable?
The 2018 Audi S4 has 2 known issues compiled from NHTSA recalls, manufacturer TSBs, and owner forum reports. 2 issues are rated critical: EA839 3.0T Water Pump Internal Seal Failure Leaks Coolant Into the Vacuum System (Class Action) and Seat-Heater Cable Contact Fault Disables the Passenger Airbag (Recall 21V874 / 74E3). 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.
How much does it cost to fix common Audi S4 problems?
Repair costs for known Audi S4 issues range from $0 to $3,000, depending on the specific problem and whether you choose DIY or professional repair. The most critical issue, EA839 3.0T Water Pump Internal Seal Failure Leaks Coolant Into the Vacuum System (Class Action), typically costs $1,200-$3,000 to repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.
What is the 2018-2025 Audi S4 EA839 3.0T Water Pump Internal Seal Failure Leaks Coolant Into the Vacuum System (Class Action)?
The B9 S4's turbocharged EA839 3.0T uses a water pump whose internal seals fail, and the failure mode is unusual: coolant does not only weep externally, it is drawn INTO the engine's vacuum circuit and other places coolant should never reach, contaminating vacuum lines and compon… Repairs typically run $1,200-$3,000. Severity: high.
What is the 2018-2020 Audi S4 Seat-Heater Cable Contact Fault Disables the Passenger Airbag (Recall 21V874 / 74E3)?
On B9 S4 sedans, the cable connecting the front passenger seat heater to the Passenger Occupant Detection System (PODS) can develop a contact fault. The PODS software reads the fault as a system malfunction and switches the passenger front airbag OFF, so the airbag will not deplo… Repairs typically run $0-$0. Severity: high.
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.