2015 Audi S4 problems

The Audi S4 is the high performance variant of Audi's compact executive car A4. The original Audi S4, built from 1991 until 1994, was a performance-oriented version of Audi's 100 saloon/sedan. All subsequent S4s since 1997 have been based on the Audi A4; and as the A4 has evolved from one generation to the next, so has the S4.
Like its regular A4 counterpart, all S4 variants have had longitudinally oriented, front-mounted engines. All versions of the S4 have their transmission mounted immediately at the rear of the engine in a longitudinal orientation, in the form of a transaxle, and like all Audi "S" cars, are only available as standard with Audi's quattro all-wheel drive (AWD) system, using a Torsen-based centre differential system. A more powerful internal combustion engine, larger upgraded brakes, firmer suspension, larger wheels, and distinctive sheetmetal, styling clues and badging have always been amongst the many upgrades the S4 receives over its mainstream 100 and A4 siblings. In markets where the even higher-performance Audi RS 4 is not offered, the S4 is the top-of-the-line trim of the A4 family.
A single turbocharged 2.2-litre inline five-cylinder powered the original C4 version, and a 2.7-litre twin turbocharged V6 engine was found in the B5 generation. The B6 and B7 versions shared a common 4.2-litre V8 engine, the first time that a V8 engine was placed in a compact executive car, placing it in direct competition with the BMW M3 (3.2 L inline 6) and Mercedes-Benz C32 AMG (3.2-litre supercharged V6). The B8 generation uses a supercharged 3.0-litre V6 TFSI engine and competed with the BMW 335i, BMW 335i/340i xDrive, and Mercedes-Benz C350. The current B9 generation is powered by a turbocharged 3.0-litre V6 TFSI engine, with rivals including the BMW M340i xDrive and Mercedes-Benz C450 AMG/Mercedes-AMG C43 4MATIC.
All versions of the S4 have been manufactured at Audi's plant in Ingolstadt, Germany; they are, or have been available as a four-door five-seat saloon and a five-door five-seat Avant (Audi's name for an estate car/station wagon) body styles since the model's inception in 1991. A two-door four-seat Cabriolet (convertible) S4 variant was introduced as part of the B6 and B7 generation A4 lineups. The B8 Cabriolet has now been built off the A5 coupe body style and the "S" variant is marketed under the Audi S5 nameplate.
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Common 2015 Audi S4 problems
The Audi S4, a high-performance sedan, has been known for its reliability and potential for aftermarket improvements. However, like any vehicle, it is not without its common problems. This article will discuss some of the most frequently reported issues with the Audi B8/B8.5 S4, based on complaints from owners.
- Cooling System: The early model B8 S4 had two inherent weaknesses in the cooling system: the water pump and the thermostat. Both components were subject to multiple recalls due to failures. The water pump housing was originally plastic but was revised with a metal housing version. The thermostat is harder to visually inspect, as it is inside the thermostat housing. It is recommended to check the service records to see if the recall has been performed. For a safe bet, you can replace it yourself as well as perform the cooling system refresh with an Assembled by ECS Cooling System Refresh kit.
- Sunroof Deflector Noise: According to some owners, the sunroof deflector creates noise with the windows down that has been described as less than comfortable. Your sunroof may or may not have had this replaced. The correct part number for the updated version is 8D9-877-651-A.
- Power Steering Wandering: In B8.5 S4s, which had electromagnetic steering systems, owners report steering wandering. This is the result of software issues and can only be fixed by a dealership software update. However, the fix has yet to be found and dealerships will notify affected owners once it becomes available.
- 6spd Clutch Noise: In manual transmission models, owners have experienced 'creaking' noises from the clutch during operation. There have been multiple updates to technical service bulletins but no permanent solution has come from Audi. If you are worried about excessive clutch noise and are planning to upgrade your S4, it might be in your best interest to upgrade your clutch system with one of our performance kits.
- Brake Noise: Some owners have experienced 'brake noise' from the factory brakes. There is an updated parts list from Audi, which solves the noise issue, but we always look for an improvement, not just a replacement. If you are concerned with brake noise and are planning to add more power, it is probably a good idea to make the switch to more aggressive brake options.
- PCV Valve Failure: The PCV valve is crucial for controlling engine pressure and keeping things running efficiently. Failure is common around 60,000-80,000 miles and can be tricky to spot, but it's vital for engine performance and emission control. This part is a little more tricky to get into as it requires removal of the supercharger and it’s not a 1 person job.
- Mechatronic System Failure: All B8 S4 models have a problem with their mechatronic system. Common signs of a failing Mechatronic unit include car going in limp mode, passing gears or totally locked out gears 1,3,5,7 - which does make the driving experience pretty harsh. The IC motor and high-pressure pump are common components for failing on the DCT DSG mechatronic unit. Pressure leaks can cause the high-pressure pump to overwork and burn out. The failure of these two components are however usually secondary issues, which are misdiagnosed as the primary suspects.
These are some of the most common issues associated with the B8/B8.5 S4. With a bit of knowledge on the front end, you can make a wise purchase decision and know what to expect. Since this list is fairly short and nothing is excessively dangerous or worrisome, you can expect a solid ownership experience. These are excellent vehicles full of tons of potential.
Is the Audi S4 engine reliable?
The S4 is known to have a lot of issues like a failed thermostat, turbocharger failure, engine oil leaks, and premature brake wear, among others. Maintaining an unreliable sedan like the Audi S4 can be costly, but facing a few common issues is worth it if owning a high-performance car can give you a lot of joy.
How many miles can an S4 last?
You can expect the average Audi S4 to last up to and potentially over 100,000 miles without the need for significant repairs, but only if you take the time to perform routine maintenance while driving in a safe and controlled manner.
Is the 2015 Audi S4 supercharged?
The 2015 Audi S4 is motivated by a supercharged 3.0-liter V6 engine rated at 333 horsepower and 325 pound-feet of torque. All-wheel drive and a six-speed manual transmission come standard, while a seven-speed automated manual (S tronic) is the self-shifting option.
Is an Audi S4 a fast car?
0-60 MPH Times
Looking at the numbers, the S4 ranks above most competitors in performance. The 0-60 mph time for the Audi S4 in our testing was 4.2 seconds.
Is the Audi S4 engine reliable?
The S4 is known to have a lot of issues like a failed thermostat, turbocharger failure, engine oil leaks, and premature brake wear, among others. Maintaining an unreliable sedan like the Audi S4 can be costly, but facing a few common issues is worth it if owning a high-performance car can give you a lot of joy.
Is the 2015 Audi S4 fast?
Performance & mpg
In Edmunds performance testing, a manual-equipped S4 accelerated from zero to 60 mph in a swift 4.9 seconds. An S4 with the automated manual bested that time with an even quicker 4.5-second run.
How many miles can an S4 last?
You can expect the average Audi S4 to last up to and potentially over 100,000 miles without the need for significant repairs, but only if you take the time to perform routine maintenance while driving in a safe and controlled manner.
Is Audi A4 or S4 better?
S4 Horsepower. Whichever model you choose, enjoy responsive power delivery and a smooth and quiet ride. The 2023 Audi A4 delivers 201 horsepower or 261 horsepower, depending on the engine option you choose, while the 2023 Audi S4 equipped with the larger V6 engine produces a mighty 349 horsepower.
2015 Audi S4 car problems categorized by type of issue
After analyzing all complaints sent to the NHTSA and researching popular Audi S4 problems, we found that the most common problems with these 2023 model year vehicles are:
- Engine problems
The graph below shows statistics for all 2015 Audi S4 vehicle components and the number of complaints received.
2015 Audi S4 complaints
The NHTSA has received 1 complaints about various vehicle components related to the 2015 Audi S4.
ENGINE PROBLEM
- Date Of Incident: 2023-01-09
- VIN: WAUBGAFL7FA
- Components: ENGINE
- Summary: The R&R valve/oil separator unit failed on my 2015 Audi S4 at approximately 71,000 miles. This unit, when fails, can mix the oil and anti-freeze which can seize the engine. I was able to catch the problem before engine failure. Minneapolis Audi repaired the vehicle this week, 1/10/23. There were NO warning indicators except noise. Various media sources have stated that this is a known engine failure concern between 60-90K miles for this engine. Audi does not recognize this as a safety or warranty concern.
2015 Audi S4 recalls
The National Highway Traffic Safety Administration (NHTSA) has issued 1 recalls for different components of the 2015 Audi S4.
- Manufacturer: Volkswagen Group of America, Inc.
- Components: AIR BAGS
- Summary: Volkswagen Group of America, Inc. (Volkswagen) is recalling certain model year 2013-2015 Audi A4 and S4 vehicles manufactured February 16, 2012, to October 21, 2014, and 2013-2015 Audi Allroad vehicles manufactured March 12, 2012, to October 21, 2014. Due to an improper algorithm in the air bag control module, if a crash necessitates deployment of the side air bags, a second impact to the front of the vehicle may not command the front air bags to also deploy.
- Consequence: If the front air bags do not deploy in the event of a secondary impact to the front of the vehicle, there is an increased risk of occupant injury.
- Remedy: Volkswagen will notify owners, and Audi dealers will update the air bag control unit software, free of charge. The recall began on November 14, 2014. Owners may contact Audi customer service at 1-800-822-2834. Volkswagen's number for this recall is 69K5.
Negative 2015 Audi S4 car reviews
Positive 2015 Audi S4 car reviews
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I was torn between the S4 and the 335i, but I'm so happy I went with the Audi! I've had the car for two years now and I've learned a lot. Let me get straight to the point and mention the negatives first. The transmission can be a bit clunky and the handling isn't as confident-inspiring as my previous Genesis coupe. Additionally, I prefer the MB Command or Porsche interface over the MMI. However, these are the only cons I can think of. The car accelerates as well as any 3.0L S'charged sport sedan and the brakes are fantastic with a consistent feel. The seats aren't plush, but they won't give you any issues. I drove from FL to NY and didn't feel too bad. The build quality is top-notch and my brother, who has the F30 328xi, agrees that the Audi feels more sturdy.
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I am so impressed with this car! A professional race driver took it for a spin on the track and was blown away by its ability to hug the road. The acceleration is fantastic, whether you're starting from a stop or need to pass someone quickly. And with the back seats down, there's an incredible amount of space. I've even managed to fit 8-foot landscaping timbers and hundreds of pounds of soil and fertilizer in the car with the trunk closed! The only thing to keep in mind is that it's not the most spacious or comfortable for four adults in the back seat.
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I think BMW cars have become too soft, similar to American muscle cars of the past with lots of power but not enough handling. Although I sold a 2013 128i M Sport after just 9 months, I had the opportunity to drive the 2015 M235i and M3 sedans all day long at the BMW Car Control event. However, I was not very impressed with the new M3. The seating position was poor, turbo lag was prevalent, and it actually had too much torque to be fun. In the past, I have had some unreliable VW and Audi cars. On a whim, I decided to look at the S4, which I had not really considered before, but maybe that's a good thing. It looks like a
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I used to own a 2006 Corvette and a 05 Acura TL. This car is like a combination of both! I chose it for the security of the AWD, but it handles well on the highway, is super comfortable, and in S mode, it's quite fast. I opted for the upgraded leather and tech package, and all in all, it feels like it cost easily $40,000 more than what I paid for it. It's not a flashy car, but it's understated and beautiful. I'll be returning it at the end of the lease in a month, and I'll definitely miss it. If I had to nitpick, the computer is a bit slow to boot up, and there's a lack of music for a few minutes after starting the car. My wife's Escape Sync system is better. The styling tends to blend in, so it's not a flashy car by any means, but it's still a very comfortable cruiser. I had a blast tackling the twisties in West Virginia!
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Overall, this is a great car with an excellent driving experience and plenty of power. The high-quality conservative interior and perfect B&O audio system make for a truly enjoyable ride. It's also a reliable car. If you're someone who likes to service their own car, I would advise following the standard service procedures precisely and investing in a VAG-COM cable to do car diagnostics yourself. Additionally, it's important to use only original AUDI parts. At 55K miles, be sure to replace all ignition coil packs (~$160 parts) when you put in new spark plugs. I learned this the hard way when one ignition coil pack gave up and I had a
Additional sources
More sources of information about 2015 Audi S4 problems:

2015 S4 Reliability
Oct 24, 2017 ... Seriously. The entire B8.5 A4, S4 lineup is very reliable as long as they are maintained properly. As long as they aren't treated like corollas ...

B8.5 S4 Reliability : r/AudiS4
Feb 16, 2021 ... Hey guys,. I'm looking to buy an 2014-2015 s4. I was just wondering what problems to expect/ what problems you've had personally.
Common Problems with the Audi B8/B8.5 S4 – ECS Tuning
Jun 2, 2020 ... Common Problems with the Audi B8/B8.5 S4 · It's not just for BMWs. · According to some owners, the sunroof deflector creates noise with the ...
Audi S4 Problems and Complaints - 17 Issues
Top Audi S4 Problems · Overheating Due to Failing Thermostat · Inspect CV Boots and Joints at Each Service · Check Engine Light Due to Faulty Torque Converter.
2015 Audi S4 Problems | Kelley Blue Book
How reliable is the 2015 Audi S4? See the most common repairs performed and learn if your vehicle is at risk for major repairs in the next 12 months.
Otho Hayes 2024-08-20
Hi there! I wanted to share my experience with the S4 that I recently purchased. Unfortunately, I had some issues with the brakes after taking it for a spin at the Infineon Raceway. The dealership determined that the rotors were bad, which was surprising to me since I've owned 10 Audi's in the past and have never had this issue before. However, I was disappointed to learn that Audi USA would not cover the cost of the brakes. Despite this setback, I still believe that Audi makes great cars and I hope to continue being a loyal customer. Thanks for listening!
Ben Williamson 2024-04-12
I purchased this car brand new last year and initially loved every aspect of it, despite some minor issues. However, I did experience some frustration with wind blowing through the windows while listening to talk radio on the highway. Additionally, my S4 came equipped with the Upgraded Summer Tire package featuring the Continental Conti Contact 3s, which unfortunately turned out to be the worst tires I have ever encountered. The tread pattern wore out unusually quickly, after only 7K miles, which was a major disappointment considering the high cost of the option. If you are considering purchasing a car with these tires, I would strongly recommend having them changed before finalizing the purchase.