2015 Audi S4 Problems: 5 Known Issues
2015 model year · 107+ owner reports · Updated October 2026
According to Au7o's analysis of 107+ owner reports, the 2015 Audi S4 has 5 documented known issues, with 2 rated critical. The most serious are Airbag-Control Software May Miss Front-Airbag Deployment After a Second Impact (Recall 14V667 / 69K5) and 0B5 DL501 S tronic Mechatronic Unit Failure - Harsh Shifts, Erratic Gear Selection and Limp Mode ($1,800-$7,000 repair). The most commonly reported issue is Thermostat Housing Failure and Coolant Leak with 107 owner reports. Across all issues with published estimates, repair costs range from $300 to $7,000. DIY maintenance guides at au7o.io.
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All 5 Known Issues
NHTSA Recalls2 recalls
AIR BAGS
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.
FUEL SYSTEM, GASOLINE:FUEL INJECTION SYSTEM:FUEL RAIL
Volkswagen Group of America, Inc. (Volkswagen) is recalling certain model year 2011-2012 Audi S4, S5, Q7, 2012 Audi A6, Volkswagen Touareg Hybrid, and 2012-2013 Audi A7 vehicles. In the affected vehicles the fuel injection system may experience a fuel leak.
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Frequently Asked Questions
What are the most common Audi S4 problems?
According to Au7o's analysis of 107+ owner reports, the 2015 Audi S4 has 5 documented issues. The most frequently reported are: Airbag-Control Software May Miss Front-Airbag Deployment After a Second Impact (Recall 14V667 / 69K5), 0B5 DL501 S tronic Mechatronic Unit Failure - Harsh Shifts, Erratic Gear Selection and Limp Mode, Thermostat Housing Failure and Coolant Leak. Of these, 2 are rated critical and should be addressed promptly.
Is the Audi S4 reliable?
The 2015 Audi S4 has 5 known issues documented across 107+ owner reports. 2 issues are rated critical: Airbag-Control Software May Miss Front-Airbag Deployment After a Second Impact (Recall 14V667 / 69K5) and 0B5 DL501 S tronic Mechatronic Unit Failure - Harsh Shifts, Erratic Gear Selection and Limp Mode. 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 $300 to $7,000, depending on the specific problem and whether you choose DIY or professional repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.
What is the 2013-2015 Audi S4 Airbag-Control Software May Miss Front-Airbag Deployment After a Second Impact (Recall 14V667 / 69K5)?
On certain 2013-2015 S4 vehicles, an airbag-control algorithm may fail to command the front airbags after a side-airbag deployment followed by a second frontal impact. Severity: high.
What is the 2010-2016 Audi S4 0B5 DL501 S tronic Mechatronic Unit Failure - Harsh Shifts, Erratic Gear Selection and Limp Mode?
S4s ordered with the 7-speed S tronic dual-clutch use the 0B5 (DL501) gearbox, whose mechatronic control unit - the valve body with its integrated solenoids, pressure sensors and TCU - is a documented weak point in high-torque applications like the S4. Failures start as harsh or… Repairs typically run $1,800-$7,000. Severity: high.
What is the 2010-2016 Audi S4 Thermostat Housing Failure and Coolant Leak?
The plastic thermostat housing on the S4 3.0T is prone to cracking and leaking coolant. The housing sits under the supercharger, making leaks hard to spot until coolant loss is significant. Repairs typically run $300-$800. Severity: medium.
What is the 2010-2016 Audi S4 Supercharger Coupler (Isolator) Wears Out and Rattles Like a Bag of Marbles?
The B8/B8.5 S4's Eaton TVS roots supercharger drives its rotor pack through a plastic coupler disc between the drive snout and the driven rotor. Over time the drive holes in that plastic coupler elongate and wear, and the slop shows up as a distinct rattling / marbles-in-a-can no… Repairs typically run $400-$1,500. Severity: medium.
What is the 2010-2016 Audi S4 3.0 TFSI PCV / Air-Oil Separator Diaphragm Ruptures, Causing Oil Consumption and a Crankcase Vacuum Leak?
The supercharged 3.0 TFSI's crankcase ventilation module (PCV / air-oil separator) uses an internal diaphragm that hardens and tears. When it does, the engine pulls unmetered air through the crankcase, gives up its ability to control crankcase pressure, and starts drawing oil int… Repairs typically run $300-$900. Severity: medium.
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.