Showing the 2021 S4 Prestige. We haven't verified this trim's engine; the numbers below cover every version of this model year. Every version
Owner complaints, recalls, fuel economy and safety ratings from public NHTSA and EPA data, updated Oct 18, 2026.
Fuel economy
23 mpgcombined; city 20, highway 28; every version of this model year
Five years of fuel
$17,500U.S. average; Ohio $16,490 at local prices; every version of this model year; fuel only, not other costs of owning it; 15,000 miles a year, at EIA fuel prices for the week of Oct 12, 2026
NHTSA's VIN data lists these trims for the 2021 S4. A trim's engine and numbers are shown as its own only where EPA names versions after the trim and no other version could be it; "seen with" means a source shows that engine on the trim, not that it was the only one. Recalls and complaints cover the whole model year: whether a recall applies to a car depends on its VIN, on NHTSA's recall lookup.
Owners have filed 2 complaints with NHTSA about the 2021 S4. These are unverified owner reports, counted by the part of the car they name; one complaint can name several parts. Counts aren't adjusted for how many were sold, so they don't show how reliable a car is.
Complaints by part of the car
Part
Complaints
Crashes
Fires
Injuries
Electrical system
1
0
0
0
Unknown or other
1
0
0
0
What the columns count
Complaints: complaints that name that part. One complaint can name several parts, so the rows overlap and don't add up to the total.
Crashes and Fires: complaints that report one. Two owners can file about the same event, and NHTSA doesn't link them, so these count reports, not events.
Injuries: the number of people the complaints say were injured.
None of these columns shows that a part caused a crash, fire or injury: they're what owners reported, unverified.
Complaints by model year
Newer years have had less time to collect complaints, and counts aren't adjusted for sales, so a shorter bar doesn't mean a more reliable year.
NHTSA lists 4 recall campaigns for the 2021 S4 over its history. Campaigns are matched by model and year, so each one may apply to a given car, and its repair may already be done: check a VIN on NHTSA's recall lookup for the open recalls on that exact car.
Back over prevention: display function
NHTSA campaign 22V742000 · reported Oct 5, 2022 · 170,296 vehicles potentially affected across the whole campaign
Remedy: Dealers will update the infotainment unit software, free of charge. Owner notification letters were mailed October 25, 2022. Owners may contact Audi's customer service at 1-800-253-2834. Volkswagen's number for this recall is 91DZ.
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."
Risk: A blank rearview camera display can reduce the driver's rear visibility, increasing the risk of a crash.
NHTSA campaign 22V034000 · reported Jan 26, 2022 · 31,058 vehicles potentially affected across the whole campaign
Remedy: Dealers will inspect the rear axle, adjust the alignment as necessary, and replace any prematurely or unevenly worn tires, free of charge. Owner notification letters were mailed March 3, 2022. Owners may contact Audi customer service at 1-800-253-2834. Audi's number for this recall is 42L5.
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.
Risk: Rear axle misalignment may cause premature or uneven tire wear, increasing the risk of a crash.
NHTSA campaign 21V606000 · reported Aug 5, 2021 · 45,496 vehicles potentially affected across the whole campaign
Remedy: Dealers will inspect, and replace as necessary, the middle-rear seat belt assemblies, free of charge. Owner notification letters were mailed August 27, 2021. Owners may contact Volkswagen customer service at 1-800-893-5298 and Audi customer service at 1-800-253-2834. Volkswagen's numbers for this recall are 69CR (VW) and 69CS (Audi).
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."
Risk: An unsecured child restraint system can increase the risk of injury during a crash.
NHTSA campaign 21V295000 · reported Apr 26, 2021 · 40,993 vehicles potentially affected across the whole campaign
Remedy: Dealers will replace the lock nuts and, if necessary, the associated bolts, free of charge. Owner notification letters were mailed June 4, 2021. Owners may contact Audi customer service at 1-800-253-2834. Audi's number for this recall is 42L1.
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.
Risk: A broken lock nut may misalign the rear axle, causing a loss of control and increasing the risk of a crash.
Carmakers sent NHTSA 969 service bulletins and notices that cover the 2021 S4, the latest on Sep 25, 2026. They tell dealers how to fix known issues.
The parts they mention most: electrical system (316), equipment (226), unknown or other (107), structure (93), steering (46).
NHTSA hasn't opened a defect investigation that covers this model year.
Maintenance
Oil
The owner's manual gives the oil and how often to change it. We show oil facts only once we've checked them against the manual, and we haven't yet for the 2021 S4.
EPA class: compact cars. EPA greenhouse gas score: 5 out of 10. Each version EPA tested:
Swipe the table sideways for more columns.
Version
Engine
Transmission
Fuel
City / hwy / comb
S4 All-Wheel Drive
3.0 L, 6 cyl, turbo
Automatic (S8)
Premium Gasoline
20 / 28 / 23
Sources and dates
U.S. EPA fuel economy data, file of Sep 29, 2026
NHTSA owner complaints, file of Oct 18, 2026
NHTSA recalls, file of Oct 18, 2026
NHTSA manufacturer communications, file of Oct 18, 2026
NHTSA defect investigations, file of Oct 18, 2026
NHTSA 5-Star Safety Ratings, file of Aug 7, 2026
U.S. Energy Information Administration, file of Oct 12, 2026
Fuel cost: EPA mpg with fuel prices for the week of Oct 12, 2026 and electricity prices for Jul 2026. Source: U.S. Energy Information Administration (Oct 2026). Complaints are unverified reports owners filed with NHTSA. About the data