2021 Audi S4 Reliability ReportCommon Problems, Repair Costs & Expert Verdict
Quick Facts · 2021 Audi S4
- Has 4 NHTSA recalls on record — the most notable involves the seat belts:rear/other:retractor.
- Scores 6 points below the strongest nearby year — the 2022 Audi S4 earns a 88.
- The system most likely to surface first: engine cooling system (moderate severity).
Should You Buy the 2021 Audi S4?
The 2021 Audi S4 offers an intoxicating blend of performance and luxury, making it a compelling choice for enthusiasts. While generally well-engineered, its sophisticated systems and premium components translate to higher-than-average running and repair costs, requiring a disciplined approach to maintenance to avoid significant financial surprises.
The 2021 Audi S4 is an outstanding performance luxury sedan that offers a fantastic driving experience and a high-quality cabin. While its core mechanicals are robust, ownership comes with the expectation of higher maintenance costs and a moderate risk of expensive repairs for its complex systems. Buy with caution,…
Best Model Years
2021-Present (B9.5 generation, with minor improvements over earlier B9)
Years to Avoid
Earlier B9 (2018-2020) models had more reported issues with initial software and some components, although many were resolved under warranty. Not inherently 'bad' but later models are slightly more refined.
Biggest Strengths
- Robust 3.0T V6 engine (EA839) when properly maintained
- Exceptional 8-speed ZF automatic transmission
- Superior interior build quality and technology integration
Top Risk Areas
The systems that tend to fail first on the 2021 Audi S4, with the typical mileage window when each becomes a concern. Detailed repair-cost ranges and exact what-to-check inspection notes are in the full report.
Failures of the water pump or thermostat housing are not uncommon on earlier versions of this engine and can lead to coolant leaks or overheating. While improved on the B9.5, it remains a potential weak point due to plastic components.
The complex MMI system can experience glitches, freezes, or connectivity issues. Parking sensors, blind-spot monitoring, and other electronic modules can also exhibit intermittent failures, often requiring software updates or module repl…
Due to the S4's performance tuning and stiff ride, suspension components like control arm bushings, ball joints, and potentially adaptive dampers (if equipped) can wear prematurely, leading to clunks, rattles, or reduced handling precision.
2021 Audi S4 Mileage Danger Zones
The mileage windows when the 2021 Audi S4 most commonly needs attention. Plan ahead, budget accordingly, and inspect before you cross each threshold.
Initial Check-up Zone
At this mileage, the car is still relatively new but may be due for its first set of brake pads if driven hard. It’s also a good time for a thorough inspection of tires and fluid levels.
Maintenance & Minor Wear Zone
Spark plugs are typically due around this point. Begin to pay closer attention to suspension components for early signs of wear, and consider a transmission fluid service if not already performed.
Elevated Component Risk Zone
This mileage brings an increased likelihood of needing to address cooling system components (water pump, thermostat) and further suspension wear items. PCV valve issues might also start to surface.
High Risk & Major Service Zone
Beyond 100k, you're entering the territory where larger, more expensive components like the turbocharger, major electrical modules, or even significant engine/transmission work could be necessary. Proactive maintenance is paramount.
2021 Audi S4 Ownership Cost Outlook
What it typically costs to keep the 2021 Audi S4 on the road. Full 5-year cost-of-ownership projection and major-failure-risk forecast are in the report.
Annual Maintenance
$600-1,000
Moderate Repairs
$1,000-2,500 occasionally
How Long Does the 2021 Audi S4 Last?
Focus on vehicles with documented service histories. While the S4 can easily exceed 150,000 miles with proper care, be prepared for increased component wear and potential major service items as mileage climbs past 90,000.
What 2021 Audi S4 Owners Actually Say
What Owners Love
- Effortless and exhilarating acceleration from the turbocharged V6
- Precise handling and composed ride, especially with adaptive suspension
- Luxurious, high-quality interior with excellent materials and ergonomics
- Sophisticated Quattro AWD system provides confidence in all conditions
Common Frustrations
- Premium fuel economy can be disappointing, especially with spirited driving
- Stiff ride can be uncomfortable on rough roads, even in 'Comfort' mode
- Rear seat legroom is tight for adults on longer journeys
- Cost of maintenance and parts is significantly higher than non-luxury brands
Who Should Buy the 2021 Audi S4?
Best For
- Driving enthusiasts who prioritize performance, handling, and daily usability
- Individuals who appreciate a luxurious, tech-forward interior and premium build quality
- Drivers in climates requiring excellent all-wheel-drive capability
Not Ideal For
- Budget-conscious buyers seeking minimal long-term ownership costs
- Individuals who require abundant rear passenger space for frequent use
How the 2021 Audi S4 Compares to Rivals
The S4 strikes a superb balance between exhilarating performance, luxurious comfort, and sophisticated technology. It generally holds its own against key German rivals in reliability, but often surpasses others in interior execution and AWD capabilities.
More Reliable Than
- Mercedes-AMG C43 (often higher electronic complexity issues)
- Infiniti Q50 Red Sport (less refined interior, inconsistent build quality)
Comparable To
- BMW M340i (similar performance, maintenance profile)
- Genesis G70 3.3T (excellent value, slightly less established long-term reliability)
NHTSA Recalls
4 recalls on record from NHTSA. Check your VIN atnhtsa.gov to see if the repair was performed.
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.
What breaks on the 2021 Audi S4?
Full reliability breakdown — engine, transmission, rust, electrical. With repair costs and mileage danger zones.
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Audi S4 by Year
Compare KeepScores across nearby years of the Audi S4. Click any year for its full report.
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Frequently Asked Questions
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