Audi A6 MOT Failures
An analysis of 623,556 real DVSA MOT tests on the Audi A6 — what fails, how often, and how that compares to every other car on UK roads. Generations covered: C5 (1997–2004), C6 (2004–2011), C7 (2011–2018), C8 (2018–2024).
Where the Audi A6 fails its MOT
The single biggest MOT failure point on the Audi A6 is light unit fault — this model is 31 times more likely to fail on this item than the average car on UK roads. That makes it a significant weak point for anyone buying or owning this model. Across 623,556 MOT tests, 0.06% of all Audi A6 tests recorded this as a failure.
Lighting faults are usually straightforward to fix (bulbs, connectors, earth points) but can indicate deeper wiring issues on older cars. Check all lights including fog lamps, number plate lights, and dashboard warning lights.
Other notable weak points include coil springs broken (71x the fleet average), anti-roll bar links worn (20x the fleet average), emissions failure (13x the fleet average), and any fracture or welding defect on a wheel (35x the fleet average). These ratios compare the Audi A6's failure rate on each item against the national average for all cars tested — a ratio of 10x means this model fails ten times more often than a typical car.
The failures span 6 categories: Lights & Electrics, Suspension, Exhaust & Emissions, Wheels, Brakes and others. If you're inspecting a Audi A6 before purchase, these are the areas to focus on — and if any have been flagged as advisories on a previous MOT, they're likely to become failures in the near future.
How failures change with mileage
The Audi A6's weak points shift as the car covers more miles. Understanding these patterns helps you know what to expect — and what to budget for — at each stage of ownership.
Under 60,000 miles
At this mileage, most failures are either design-related or caused by age rather than wear. Components like bushes and drop links may not have been replaced yet, and original-fit parts can deteriorate even on low-mileage cars that spend a lot of time sitting.
For the Audi A6 specifically, the DVSA data shows the most common failures at this mileage are coil springs broken (71x the average) and anti-roll bar links worn (18x). any fracture or welding defect on a wheel (14x) and headlight fault (11x) also appear frequently.
60,000 to 100,000 miles
This is where routine wear items start to show up. Brake components, tyres, and exhaust parts have done serious work by this point. Cars that have been well serviced will show fewer of these failures — this mileage band is where good maintenance really separates the well-kept from the neglected.
For the Audi A6 specifically, the DVSA data shows the most common failures at this mileage are any fracture or welding defect on a wheel (35x the average) and light unit fault (24x). rear registration plate lamp or light source mi... (18x) and brake hoses perished or damaged (17x) also appear frequently.
Over 100,000 miles
High-mileage cars accumulate failures across multiple systems. The key question isn't whether things will need doing — they will — but whether the car has been maintained well enough to keep on top of them. Look for a consistent service history and recent MOT passes with minimal advisories.
For the Audi A6 specifically, the DVSA data shows the most common failures at this mileage are coil springs broken (38x the average) and light unit fault (25x). body panel damage (22x) and suspension component damaged or corroded (20x) also appear frequently.
Known issues beyond the MOT
An MOT only tests roadworthiness at a single point in time — it won't catch developing faults, intermittent problems, or issues that haven't yet reached the failure threshold. These are the issues that Audi A6 specialists and owners flag most frequently, drawn from manufacturer technical bulletins, workshop data, and verified owner reports.
Oil pump drive failure (C6) Dangerous
The oil pump drive on PD TDI engines is secured by a single hex bolt that can shear without warning, causing immediate loss of oil pressure and catastrophic engine failure. Affects C6; typical independent garage repair cost is £1,500–£3,000.
Swirl flap failure (C6) Dangerous
The intake manifold swirl flaps on V6 TDI engines can break and fall into the cylinders, causing catastrophic internal engine damage. Affects C6; typical independent garage repair cost is £500–£1,500.
Timing chain tensioner and cam follower failure (C6) Dangerous
The EA888 generation 1 engine suffers from two critical failures: timing chain tensioner wear causing chain stretch and jump, and high-pressure fuel pump cam follower wear that can destroy the camshaft. Affects C6; typical independent garage repair cost is £600–£1,500.
Turbocharger failure (C5) Major
The 2.7T Biturbo uses twin K03 turbochargers that are prone to bearing failure, particularly the turbine-side bearings. Affects C5; typical independent garage repair cost is £1,500–£3,000.
For the complete picture — including repair costs across independent, specialist, and dealer garages — see the full Audi A6 common problems breakdown.
What to check before buying a Audi A6
Based on the MOT failure data and known issues above, here's what to prioritise when inspecting a Audi A6:
Lights & Electrics — check for light unit fault, headlight fault. Suspension — check for coil springs broken, anti-roll bar links worn. Exhaust & Emissions — check for emissions failure.
Beyond the MOT items, ask specifically about oil pump drive failure and swirl flap failure. These won't show up on a standard MOT but can be expensive to fix — repairs start from £1,500. A specialist pre-purchase inspection is worth the investment on this model.
Always check the car's full MOT history for patterns — recurring advisories often become failures within 12 months. And verify the service history to confirm maintenance has been kept up to schedule. Enter any reg into our free car check to see the complete picture.
Looking at a specific Audi A6?
Enter the reg to see its full MOT history, mileage records, write-off status, and finance checks.
Audi A6 MOT FAQs
What are the most common MOT failures on a Audi A6?
Based on 623,556 DVSA MOT tests, the most common failure is light unit fault — at 31x the national fleet average. Other frequent failures include coil springs broken and anti-roll bar links worn.
Is the Audi A6 reliable based on MOT data?
The Audi A6 has 18 MOT failure categories above the fleet average. Specialists also flag oil pump drive failure as a concern. A pre-purchase inspection and service history check are recommended.
What MOT failures should I expect at high mileage?
Above 100,000 miles, the Audi A6 most commonly fails on coil springs broken and light unit fault. Under 60,000 miles, the main issues are coil springs broken and anti-roll bar links worn.
How do I check a Audi A6's MOT history?
Enter the registration number into our free car check above. You'll see every MOT test result, advisories and failures, mileage readings, write-off status, and finance checks.
MOT failure data sourced from DVSA bulk test records via data.gov.uk. Ratios compare this model's failure rate against the national fleet average. Known issues sourced from manufacturer bulletins, specialist workshops, and verified owner reports.