Audi A8: common faults & what to check

Which Audi A8 are you looking at?

3 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

3 variants documented

2002–2010D32002–2010D3Engine not documented for this generationEngine not documentedDocumented issues4 knownSee faults & what to checkPhoto: OSX via Wikimedia Commons, Public domain.

2010–2018D42010–2018D4Engine not documented for this generationEngine not documentedDocumented issues4 knownSee faults & what to checkPhoto: EurovisionNim via Wikimedia Commons, CC BY-SA 4.0.

2017–nowD52017–nowD5Engine not documented for this generationEngine not documentedDocumented issues3 knownSee faults & what to checkPhoto: Vauxford via Wikimedia Commons, CC BY-SA 4.0.

Now narrow it to the engine

A 1.8 and a 2.4 of the same car do not fail the same way, so the faults below narrow to the engine as well as the year. Free, no account needed.

Start your free check on this Audi A8

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 A8 before you hand over any money. Every documented fault is listed below, each with its own page.

• Serious issue

  Check ride height at all four corners when cold — any low corner indicates a failed strut.

  See why

  Air Suspension Strut Failure and Compressor Burn-Out

  All D3, D4, and D5 Audi A8 models use Audi Adaptive Air Suspension as standard across all four corners. Air spring bladders degrade from ozone cracking, UV exposure, and heat cycling — D3 cars (2002-2009) are now 17-24 years old in the NZ/AU market, making strut failure essentially expected. The air compressor overworks to maintain pressure against leaking struts and burns out within months of first strut failure. D4 compressor failure is particularly well-documented due to the compressor being in an enclosed location with poor ventilation. A car sitting on its bump stops fails WOF in NZ/AU. Coilover conversion is a common but ride-quality-compromising workaround seen frequently at the price point these cars trade at.

  What you would notice

  • Vehicle sitting lower than normal at one or more corners
  • Suspension fault or 'raise vehicle' warning on MMI display
  • Air compressor audible cycling repeatedly after startup
  • Harsh, undamped ride quality with no height adjustment response
  • Visible lean or tilt when parked on level ground

  Typically $1,400–$8,000 to put right.

• Serious issue

  Cold-start the engine and listen carefully for chain rattle from the front — any rattle that disappears after 20-40 seconds is a strong indicator.

  See why

  3.0 TDI V6 Timing Chain Tensioner Failure

  The 3.0-litre TDI V6 diesel (ASB, CDSA, CREC, and related codes in D3 and D4 A8) shares the documented timing chain tensioner failure that affects the VW/Audi 3.0 TDI engine family. The hydraulic chain tensioner loses pressure at cold start when oil viscosity is high and oil pressure takes time to build, allowing chain slack. Over time the plastic guides wear down, followed by chain stretch. Failure is silent until advanced — cold-start rattle is the primary warning. If the chain jumps a tooth, catastrophic valve-to-piston contact results. This fault is acknowledged across the A6, A7, A8, and Q7 with 3.0 TDI and is a known issue to any Audi-experienced workshop in NZ/AU.

  What you would notice

  • Cold-start timing chain rattle from front of engine (disappears within 30 seconds as oil pressure builds)
  • Camshaft position correlation fault codes (P0016, P0017 range)
  • Rough running during cold warm-up phase
  • In severe cases: engine failure or bent valves if chain jumps a tooth

  Typically $2,800–$7,500 to put right.

• Serious issue

  Ask to see evidence of cam follower inspection records — this is a standard check item on any informed Audi specialist service.

  See why

  4.2 FSI V8 Cam Follower and HPFP Drive Wear

  The 4.2-litre FSI V8 (BFM, CAUA, and related codes, in D3 and D4 A8) shares the high-pressure fuel pump cam follower wear defect documented across the entire Audi/VW FSI engine family. The mechanical HPFP is driven by a dedicated lobe on the intake camshaft via a small roller follower. This follower is under-lubricated and wears through rapidly — typically at 40,000-80,000 km on unmonitored cars — eventually destroying the camshaft lobe. The repair window is narrow and the follower must be inspected at every oil change. Once camshaft lobe damage occurs, the repair cost escalates dramatically to include camshaft replacement. This is one of the most documented FSI failure modes across Audi forums globally.

  What you would notice

  • Hard starting or extended cranking before the engine fires
  • Misfires at idle or under light load
  • Lean mixture fault codes (P0171, P0174)
  • Ticking noise from top of engine near the high-pressure fuel pump
  • Loss of fuel pressure on live data scan

  Typically $350–$6,500 to put right.

• Serious issue

  Cold-start the engine and listen for chain rattle from either side.

  See why

  4.0 TFSI V8 Timing Chain Tensioner Failure

  The 4.0-litre twin-turbo TFSI V8 (CZAC and related codes) in the D5 A8 is documented for timing chain tensioner failure, sharing the pattern seen across the broader VW/Audi 4.0 TFSI engine family (also found in the Bentley Bentayga and Lamborghini Urus). The engine has two timing chains (one per bank) with hydraulic tensioners that can fail under extended oil change intervals or at higher mileages. Tensioner failure results in chain slack and cold-start rattle — if a chain jumps a tooth, catastrophic valve-to-piston contact results. This is less common than on the 3.0 TDI but is documented on high-mileage D5 examples and vehicles on extended service intervals.

  What you would notice

  • Cold-start timing chain rattle from one or both cylinder banks
  • Check engine light with camshaft correlation codes (P0016, P0017 range)
  • Rough running on cold start settling after warm-up
  • In advanced cases: misfires and loss of power under load

  Typically $5,500–$16,000 to put right.

• Costly issue

  Scan for 48V system fault codes using VCDS or ODIS.

  See why

  D5 Mild-Hybrid BSG (Belt-Starter-Generator) Failure

  The D5 A8 (2017-present) with the 3.0 TFSI engine uses Audi's 48V mild-hybrid system with a Belt-Starter-Generator replacing the conventional alternator and starter motor. The BSG is driven by a dedicated belt and integrates with a 10Ah lithium-ion buffer battery and a DC/DC converter linking 48V and 12V systems. Failures are documented from the BSG unit itself (bearing and winding wear), the 48V lithium buffer battery (cell degradation), and the DC/DC converter. Failure modes range from loss of mild-hybrid assist (cosmetic at first) to inability to restart the engine in emergency mode. Belt-driven units see accelerated wear in high-cycle city stop-start use. This is an emerging documented pattern given the D5's relative youth.

  What you would notice

  • Mild-hybrid system warning or deactivation message on MMI
  • Battery or charging system fault on dashboard
  • 12V battery repeatedly discharging unexpectedly
  • Audible conventional starter engagement on startup (BSG normally starts the engine silently)
  • Loss of engine-off coasting or regenerative braking capability

  Typically $2,500–$9,500 to put right.

• Costly issue

  Test drive in slow city traffic (exercising 1-3 gears) and at steady highway speed — any harsh upshift, hesitation, or gear hunting is a flag.

  See why

  ZF 8HP Transmission Solenoid Pack and Valve Body Wear

  The ZF 8HP automatic transmission fitted to D4 and D5 Audi A8 is documented for solenoid pack and valve body bore wear, particularly in vehicles that have never had transmission fluid changed — Audi marketed the unit as sealed-for-life. Degraded fluid causes solenoid sluggishness and bore wear in the valve body, resulting in harsh engagement, delayed shifts, and stored fault codes. This fault pattern is shared across all VAG/BMW/Jaguar Land Rover applications of the ZF 8HP and is well-documented to independent transmission specialists in NZ/AU.

  What you would notice

  • Harsh or jerky 1-2 or 2-3 upshifts
  • Delayed engagement from Drive or Reverse
  • Transmission warning light on MMI display
  • Fault codes in P0750-P0770 range (solenoid circuit)
  • Hunting between gears at steady cruise

  Typically $1,600–$8,500 to put right.

Audi A8 service schedule

What falls due, and at what distance, for each generation of the Audi A8. 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 A8’s documented faults are repairs other models share. Each page lists the documented NZ cost for every model it affects.

• Timing Chain Replacement Cost

Other Audi models