Audi A4 MOT Failures
An analysis of 952,634 real DVSA MOT tests on the Audi A4 — what fails, how often, and how that compares to every other car on UK roads. Generations covered: B7 (2005–2008), B8 (2008–2015), B9 (2016–2023).
Where the Audi A4 fails its MOT
The single biggest MOT failure point on the Audi A4 is brake hoses perished or damaged — this model is 71 times more likely to fail on this item than the average car on UK roads. That makes it a major concern for anyone buying or owning this model. Across 952,634 MOT tests, 7.72% of all Audi A4 tests recorded this as a failure.
Brake failures on the MOT range from worn pads and discs (routine maintenance) to corroded brake lines and seized calipers (more serious). Check for any pulling under braking and listen for grinding.
Other notable weak points include emissions failure (177x the fleet average), coil springs broken (69x the fleet average), fluid leak (693x the fleet average), and headlight fault (18x the fleet average). These ratios compare the Audi A4'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 4 categories: Brakes, Exhaust & Emissions, Suspension, Lights & Electrics. If you're inspecting a Audi A4 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 A4'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 A4 specifically, the DVSA data shows the most common failures at this mileage are fluid leak (693x the average) and emissions failure (141x). coil springs broken (69x) and brake hoses perished or damaged (61x) 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 A4 specifically, the DVSA data shows the most common failures at this mileage are fluid leak (402x the average) and emissions failure (79x). track rod ends worn (19x) and coil springs broken (18x) 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 A4 specifically, the DVSA data shows the most common failures at this mileage are emissions failure (26x the average) and time taken to build up air pressure/vacuum to s... (17x). headlight fault (15x) and wheel with more than one loose or missing wheel... (13x) also appear frequently.
The shift from fluid leak at lower mileages to emissions failure at higher mileages is typical — early failures tend to be design or factory-related, while high-mileage failures reflect accumulated mechanical wear. A car that's been well maintained will usually dodge the worst of both.
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 A4 specialists and owners flag most frequently, drawn from manufacturer technical bulletins, workshop data, and verified owner reports.
Oil pump drive hex bolt failure (B7) Dangerous
The oil pump drive on B7 1.9 TDI PD engines uses a hex bolt that can shear without warning, causing complete loss of oil pressure and catastrophic engine failure within seconds. Affects B7; typical independent garage repair cost is £1,500–£3,000.
Cam follower failure from HPFP (B7) Dangerous
The high-pressure fuel pump cam follower on B7 2.0 TFSI engines wears through due to inadequate hardening, destroying the camshaft lobe beneath it. Affects B7; typical independent garage repair cost is £200–£600.
Multitronic CVT gearbox failure (B7) Dangerous
The Multitronic CVT transmission is notoriously unreliable with widespread failures affecting the steel belt, pulleys, and control systems. Affects B7; typical independent garage repair cost is £2,000–£4,000.
Oil pump chain failure (B8) Dangerous
The balance shaft oil pump chain can fail on 2008-2012 diesel models, similar to the hex bolt issue on B7 PD engines. Affects B8; 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 A4 common problems breakdown.
What to check before buying a Audi A4
Based on the MOT failure data and known issues above, here's what to prioritise when inspecting a Audi A4:
Brakes — check for brake hoses perished or damaged. Exhaust & Emissions — check for emissions failure. Suspension — check for coil springs broken, fluid leak, suspension joint dust cover severely deteriorated, anti-roll bar links worn.
Beyond the MOT items, ask specifically about oil pump drive hex bolt failure and cam follower failure from hpfp. 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 A4?
Enter the reg to see its full MOT history, mileage records, write-off status, and finance checks.
Audi A4 MOT FAQs
What are the most common MOT failures on a Audi A4?
Based on 952,634 DVSA MOT tests, the most common failure is brake hoses perished or damaged — at 71x the national fleet average. Other frequent failures include emissions failure and coil springs broken.
Is the Audi A4 reliable based on MOT data?
The Audi A4 has 18 MOT failure categories above the fleet average. Specialists also flag oil pump drive hex bolt 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 A4 most commonly fails on emissions failure and time taken to build up air pressure/vacuum to s.... Under 60,000 miles, the main issues are fluid leak and emissions failure.
How do I check a Audi A4'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.