The RS Q8 was introduced as a 2020 model (no 2019 model exists), and the 2020-2021 variants with the 4.0T V8 are covered by NHTSA recall 21V244 for a fuel rail fitting that can loosen and leak fuel, creating a fire risk. Symptoms include a gasoline smell or visible fuel puddle. The recall repair is free; independent out-of-pocket repair is about $1,150 including parts and labor.

The RS Q8's rear driveline can develop excess backlash or dry splines, producing a loud metallic clunk or pop when shifting from Park to Reverse/Drive or under low-speed throttle changes. It can cause premature wear of driveshaft or differential flanges if ignored. Greasing the splines under a TSB typically costs around $300; if flange/driveshaft replacement is needed, expect $1,200 to $2,500.

The air suspension struts and compressor can leak from rubber bellows or O-rings, causing the vehicle to sit lower after sitting and the compressor to run constantly with a 'Suspension: Malfunction' message. If left unrepaired, the compressor can overheat and fail, leaving the car stuck on its bump stops. Replacing a strut is about $2,150 and compressor replacement is around $1,100 to $2,000, with full four-corner replacement exceeding $5,000.

The 48V battery or belt-driven starter/generator can fail, triggering a 'Start/Stop system unavailable' warning, check engine light with code P0A16, or loss of electrical power assistance and possible engine stall/limp mode. Replacing the BSG is about $2,150 including labor; the 48V lithium battery itself is $2,500 to $4,000 in parts. Ignoring it can leave the vehicle shut down while driving.

The MIB 3 infotainment system can freeze, go black, or reboot randomly while driving, and may drop Bluetooth/navigation or prevent the rear-view camera from engaging. Audi's software updates can reduce the problem but do not always fix hardware faults. A software update costs about $250 at an indie shop, while replacing the MMI control unit is $1,200 to $2,500.

The 4.0T V8's PCV/oil separator can fail, causing blue/white exhaust smoke, low oil pressure warnings, and oil consumption around one liter every 750 miles. If ignored, fouled spark plugs and severe carbon buildup can lead to expensive engine damage. Replacing the PCV/oil separator and valve cover assemblies is about $1,150; a damaged engine may require an $8,000 to $15,000 rebuild.