Audi S6: common faults & what to check

Which Audi S6 are you looking at?

4 generation variants documented. Pick the shape you recognise: the faults, the servicing and the timeline below all narrow to it. Free, no account needed.

Engine not documented

4 variants documented

1994–1997C41994–1997C4Engine not documented for this generationEngine not documentedDocumented issues0 knownSee faults & what to checkPhoto: Elise240SX via Wikimedia Commons, CC BY-SA 4.0.

2000–2011C52000–2011C5Engine not documented for this generationEngine not documentedDocumented issues0 knownSee faults & what to checkPhoto: Spanish Coches via Wikimedia Commons, CC BY 2.0.

2011–2019C72011–2019C7Engine not documented for this generationEngine not documentedDocumented issues7 knownSee faults & what to checkPhoto: M 93 via Wikimedia Commons, CC BY-SA 3.0 de.

2019–nowC82019–nowC8Engine not documented for this generationEngine not documentedDocumented issues4 knownSee faults & what to checkPhoto: Alexander Migl via Wikimedia Commons, CC BY-SA 4.0.

Start your free check on this Audi S6

No plate needed. You get the risk score, the buyer's checklist and the guided inspection for the exact car you picked above — not the whole nameplate.

The checks worth doing on a Audi S6 before you hand over any money. Every documented fault is listed below, each with its own page.

• Serious issue

  Cold-start the engine and listen for chain rattle from the front/right of the engine in the first 5-10 seconds before oil pressure builds.

  See why

  3.0 TDI B-bank Timing Chain Tensioner and Sprocket Failure

  The B-bank (right cylinder bank) timing chain tensioner loses hydraulic pressure or the plastic chain guide wears through on the CDUD and CKVB 3.0 TDI V6. The chain can jump teeth or snap, bending valves and causing catastrophic engine damage. The failure occurs without warning and is more pronounced on high-mileage examples that have not had regular oil changes with specified low-SAPS oil. Audi issued a TSB and extended warranty in some markets but this is not universally covered.

  What you would notice

  • Rattling or chattering noise from the right front of the engine on cold start that fades as oil pressure builds
  • Engine management warning light with P0016, P0017, P0018 or P0019 camshaft correlation codes
  • Rough running or misfires after the chain jumps teeth
  • Sudden complete engine failure if the chain snaps
  • Oil consumption above 0.5 L per 1,000 km as an early indicator of wear

  Typically $3,500–$22,000 to put right.

• Serious issue

  Test all gear positions including reverse for smooth engagement.

  See why

  S-Tronic DL501 Mechatronic Unit Failure

  The 7-speed DL501 S-Tronic dual-clutch gearbox fitted to A6 C7 models houses its shift solenoids, clutch pressure control valves, and electronic control module in a single mechatronic unit submerged in transmission fluid. Heat from the wet clutch pack and electrical cycling degrade the unit's circuit board solder joints and solenoid windings. Solenoid failure disrupts clutch pressure and gear-selector regulation, producing erratic shifts, limp mode, or a complete inability to select gears. The integrated design means the entire mechatronic unit must be replaced or rebuilt rather than repairing individual components.

  What you would notice

  • Harsh, jerky, or delayed gear changes — particularly 2nd to 3rd and 4th to 5th
  • Gearbox warning light and PRNDS indicator flashing on the dashboard
  • Transmission entering limp mode and refusing to shift above first or second gear
  • Loss of reverse or inability to select drive after starting the engine

  Typically $3,500–$7,500 to put right.

• Costly issue

  Park on a level surface overnight and check front ride height in the morning before starting.

  See why

  Air Suspension Front Strut Air Bladder Failure

  The C7 A6 Adaptive Air Suspension uses rubber air bladder bellows on each front strut. The front bladders are prone to cracking at the convolute folds due to rubber degradation from UV exposure, ozone, and repeated compression cycles over time. A cracked bladder causes a slow or rapid air leak, dropping the front ride height — typically most visible after the vehicle has sat overnight. The air compressor attempts to compensate by running excessively, eventually burning out the compressor motor if the leak is not repaired. Replacement with genuine Audi bladders is required for lasting reliability; budget aftermarket units carry high re-failure rates in Australasian UV conditions.

  What you would notice

  • Front of vehicle sitting noticeably lower than rear, especially after overnight parking
  • Air suspension warning or chassis fault message on MMI display
  • Compressor cycling audibly when vehicle is parked or at idle
  • Uneven front ride height left-to-right
  • Vehicle drops to bumpstops on cold mornings with advanced bladder failure

  Typically $1,600–$5,500 to put right.

• Costly issue

  Inspect ride height at all four corners for consistency.

  See why

  Air Suspension Strut Perishing and Compressor Failure (C7)

  The C7 A6 equipped with air suspension (standard on some Quattro variants and optional on others) uses air struts with rubber air bags that perish with age. Cracked air bags cause one or more corners to sag. The compressor runs continuously to compensate, overheating and burning out. Both front and rear struts fail; rear struts are the most common failure point on C7 examples in NZ. Given the age of C7 imports now entering the NZ used market, this fault is increasingly common and is frequently undisclosed by private sellers.

  What you would notice

  • Car sitting noticeably lower at one or more corners when parked
  • Air suspension or chassis fault warning on the Audi MMI cluster
  • Compressor audible running continuously from the boot area
  • Hissing noise from a wheel arch, particularly at the rear

  Typically $1,200–$5,500 to put right.

• Costly issue

  Inspect the vehicle after it has sat overnight — check all four corners are at equal, correct ride height.

  See why

  Adaptive Air Suspension Compressor and Height Sensor Failure

  The optional (and fitted as standard on many A6 variants sold in NZ/AU) Audi air suspension uses an electric compressor to maintain air spring pressure and four height sensors to communicate ride height to the control module. The compressor motor brushes wear out and the compressor membrane cracks, while the potentiometric height sensors corrode at their pivot points or suffer wiring harness chafing near the wheel arch. Both faults trigger the suspension warning light and can cause the vehicle to sit noticeably low on one or more corners overnight. Continued driving on a failed compressor accelerates air strut wear.

  What you would notice

  • Suspension warning light and message 'Suspension fault: do not exceed 80 km/h'
  • Vehicle sitting visibly lower on one corner or all corners after an overnight park
  • Audible compressor running continuously or for long periods after start-up
  • Uneven or bouncy ride quality on one axle compared to the other
  • Fault codes for height sensor implausible signal stored in the suspension control module

  Typically $900–$4,500 to put right.

• Costly issue

  Repeat at 12 and 6 o'clock positions to check wheel bearing and strut top mount.

  See why

  C7 Front Lower Control Arm Ball Joint and Bush Failure

  The C7-generation A6 uses a multi-link front suspension with aluminium lower wishbones. The pressed-in rubber bushings at the front and rear of the lower control arm deteriorate from age and road grime, causing clunking over bumps and vague steering response. More critically, the lower ball joint (either integral to the arm or a separate pressed-in unit depending on the variant) wears through its housing, producing a knocking sound under braking and cornering. A failed ball joint is a loss-of-control risk. Audi specifies replacement of the complete arm rather than bush-only or ball-joint-only repair on most configurations.

  What you would notice

  • Clunking or knocking sound from the front suspension when driving over speed bumps, pot holes, or rough road joins
  • Steering wander or vagueness on straight roads, requiring constant small corrections
  • Steering wheel pulling to one side under braking on a smooth road
  • Visible cracking or deformation of the rubber bush boots on the lower control arm
  • Premature or uneven front tyre wear across the tread width

  Typically $1,600–$4,000 to put right.

Audi S6 service schedule

What falls due, and at what distance, for each generation of the Audi S6. These are the model’s intervals — the car’s own service book is the only thing that can tell you what has actually been done to it.

What these repairs cost on other cars

Some of the Audi S6’s documented faults are repairs other models share. Each page lists the documented NZ cost for every model it affects.

• Timing Chain Replacement Cost
• DSG and Dual-Clutch Gearbox Repair Cost
• Diesel Injector Replacement Cost

Other Audi models