Used car guide

2015 Audi S6: known problems and what to check

Too few Audi S6 cars first registered in 2015 had an MOT during 2025 for reliable MOT figures. Here’s what we do know about the 2015 Audi S6, and what to check before you buy one.

94on the UK register at the end of 2025
Petrolmost common fuel (also diesel)
4known faults listed below

Known faults on the 2015 Audi S6

Reported by owners, mechanics and buying guides for this model and age. Check which engine the car has, as some apply to one engine only.

  • Automatic gearbox failure (high mileage)

    Multitronic and S tronic automatic

    Both the Multitronic and S tronic automatics can fail on high-mileage cars, and a replacement is a four-figure job.

    At the viewing: Drive in traffic and on the open road, and check for slipping, jerks or hesitation.

    Source: Carbuyer: used Audi A6 buying guide (2011-2018)

  • Oil use (diesel)

    Diesel

    The diesels can use a lot of oil. A low level can also point to poor maintenance.

    At the viewing: Check the dipstick shows full.

    Source: Carbuyer: used Audi A6 buying guide (2011-2018)

  • Fuel gauge and parking brake glitches

    All engines

    The fuel gauge can read empty with a full tank, and the electronic parking brake can refuse to release. A software update fixes both.

    At the viewing: Check the fuel gauge and that the parking brake releases cleanly.

    Source: Carbuyer: used Audi A6 buying guide (2011-2018)

  • Water in the rear lights

    All engines

    Water can get into the rear light units, and new ones are expensive.

    At the viewing: Look for condensation inside the rear lights.

    Source: Carbuyer: used Audi A6 buying guide (2011-2018)

Questions to ask the seller before buying a 2015 Audi S6

Ask before you travel to see it. A seller who knows the car will have answers, and receipts.

  1. Has the gearbox had any work, and has its oil been changed on time?
  2. Can I see the service history and receipts for any big jobs?

What to check on a 2015 car

  • MOT history

    Check the reg below: its MOT history shows what has been failed or advised, and whether the mileage adds up.

  • Service history

    Look for regular servicing and receipts for big jobs like a cambelt or clutch.

  • Finance and write-offs

    MOT records don’t show outstanding finance or insurance write-offs. A history check does.

  • Test drive

    Listen for knocks over bumps, check every warning light goes out, and make sure the gears and brakes feel right.

Looking at an Audi S6?

Check the actual car: its own MOT history, mileage and what to ask the seller. Free, no sign-up.

Other years

Every year of the Audi S6 compared

YearMOT testsMost flagged
2026–Too new for MOT data
2025–Too new for MOT data
2024–Too new for MOT data
2023–Too new for MOT data
2022–Too few tests
2021–Too few tests
2020174Tyres 22%
2019295Tyres 18%
2018–Too few tests
2017–Too few tests
2016–Too few tests
2014–Too few tests
2013–Too few tests
2012–Too few tests
2010–Too few tests
2009–Too few tests
2008–Too few tests
2007–Too few tests
2006100Lights and electrics 28%
2003–Too few tests
2002–Too few tests
2001–Too few tests
2000–Too few tests
1997–Too few tests
1996–Too few tests
1995–Too few tests
1994–Too few tests

Where this comes from: how many are on the road is from the Department for Transport’s vehicle licensing statistics (DVLA records), counted by the year each car was first registered. Known faults are from UK buying guides, in our own words, with links. How we score