Model Reports 4 min read Updated 18 Oct 2026

Audi A6 2009: reliability & common MOT faults

In 2025, 69 in every 100 first MOTs on a 2009 Audi A6 were passes. Most common reason for a fail: Diesel engine warning light.

Summary

The 2009 Audi A6 follows the pattern of the model years either side.

At a glance

How 3,678 first tests went in 2025.

Passed first time
69 in every 100
Did not pass first time
31 in every 1001,155 failed first-attempt tests
The typical car
16 yearsabout 153,668 miles
First tests counted
3,678

What failed most often

  1. Diesel engine warning light11 in every 100 failed tests
  2. Anti-roll bar linkage pins and bushes (front)10 in every 100 failed tests
  3. Tyre condition (rear)9 in every 100 failed tests

How we count this. Data: UK MOT open data, 2025. Only Class 4 cars on their first MOT of the year are counted. A car that fails and is fixed at the test station still counts as a fail in the first-attempt rate. These are raw results, not adjusted for age, mileage, or peer mix. The MOT does not test engine or gearbox internals.

Note:

These are patterns across 2009 Audi A6 vehicles in 2025, not a prediction that any one car will have them. Faults are grouped by part of the car. They come from MOT defect codes, not manufacturer bulletins, recalls or a diagnosis of any one car.

Suspension

Two faults. The strongest is the anti-roll bar linkage pins and bushes (front): 41 times as often as on similar cars.

Figures below are measured across the 1,155 failed first attempts in 2025 that had a mileage recorded, which allows a like-for-like comparison.

We only list faults with at least 20 failures and a rate of about 2.0 times that of similar cars, which keeps one-off results out of the list.

Anti-roll bar linkage pins and bushes (front)

Failed on 115 first tests41 times as often as similar carsStrong evidence

What it means

Excessive wear in an anti-roll bar linkage pin or bush is Major. If the pin or bush is likely to become detached, it is graded Dangerous. The wording is DVSA's general one for a suspension pin, bush or joint.

Also noted as an advisory

Testers also noted it as an advisory, worn but not yet failing, on 80 first tests, 18 times as often as on similar cars.

Suspension sub-frame (front)

Failed on 27 first tests5.6 times as often as similar carsPossible evidence

What it means

A suspension sub-frame insecurely attached to the chassis or axle is Major, and Dangerous when it is insecure and impairing directional stability. A sub-frame that is missing, likely to become detached, fractured or likely to fail is also Dangerous. Excessive damage or corrosion that seriously weakens it is Major.

Data: UK MOT open data, 2025. Compared with cars of the same age and mileage. Advisories count notes recorded on failed first tests only.

Seat belts and restraints

One fault: seat belt condition (rear), 6.6 times as often as on similar cars.

Seat belt condition (rear)

Failed on 67 first tests6.6 times as often as similar carsLikely evidence

What it means

Any sign of overstretching is a deficiency, and so is a cut anywhere on a child seat belt. On other belts the size of a cut decides it, with a stricter limit at the webbing edge than away from it. Webbing significantly stretched or weakened has rows in both Major and Dangerous grades.

Data: UK MOT open data, 2025. Compared with cars of the same age and mileage.

Noise, emissions and leaks

One fault: diesel engine warning light, 2.9 times as often as on similar cars.

Diesel engine warning light

Failed on 129 first tests2.9 times as often as similar carsPossible evidence

What it means

An engine malfunction indicator lamp that is illuminated to show a malfunction is graded Major on a diesel, but only on the diesels the test covers, which depends on the vehicle type and when it was first used. DVSA lists it under exhaust emissions for compression ignition engines, and the detail line for the row also names an inoperative lamp.

Data: UK MOT open data, 2025. Compared with cars of the same age and mileage.

Advisories

Other things testers noted as worn or close to failing, more often than on similar cars.

An advisory is a note from the tester about something that has not failed yet. It is an early warning, not a fail. Advisories for the faults above are shown with those faults.

Suspension sub-frame pins and bushes (front)

Noted on 20 first tests6.6 times as often as similar carsElevated evidence

Individual direction indicators (front)

Noted on 27 first tests3.5 times as often as similar carsElevated evidence

Flexible brake hoses (rear)

Noted on 46 first tests2.4 times as often as similar carsElevated evidence

Data: UK MOT open data, 2025. Counts cover advisories recorded on failed first tests only, compared with cars of the same age and mileage.

MOT pass rates

How first tests ended, and how the pass rates are counted.

Passed first time
69in every 100
Passed on the first test.
Fixed at the station
7in every 100
Failed, then fixed at the test station the same day.
Failed
24in every 100
Did not pass, and were not fixed at the test station.

First-attempt pass 68.6% of 3,678 first tests (2025): only cars that passed first time count. Official-style pass 75.9%: cars fixed at the test station also count as a pass. The 7 fixed and the 24 not fixed make the 31 in every 100 that did not pass first time.

Petrol and diesel

First testsTypical mileagePassed first time, as tested
Diesel3,345158,250 miles67
Petrol333100,631 miles80

Figures are in every 100 first tests.

Same model, other years

Passed first time in every 100, all tested in 2025.

4060801002005200920152020Older carsNewer cars
40608010020092020Newer cars

Newer cars are younger, so look for a jump rather than the climb. A year earlier (2024), when these cars were a year younger, 68 in every 100 passed first time.

YearPassed first timeFirst tests
200363 in every 100543
200462 in every 100754
200563 in every 1001,307
200664 in every 1002,326
200765 in every 1004,234
200865 in every 1004,491
2009 This car69 in every 1003,678
201069 in every 1005,905
201173 in every 1006,249
201278 in every 1007,442
201379 in every 1009,698
201479 in every 10010,009
201582 in every 10010,578
201683 in every 10012,385
201785 in every 1008,782
201886 in every 1007,674
201988 in every 1008,209
202090 in every 1003,222
202191 in every 1004,270
202291 in every 1003,818

If you are buying one

What this year's MOT record means for the decision in front of you.

Mileage matters most on a 2009 Audi A6.

Of 2009 Audi A6 vehicles with under 116,000 miles, 75 in every 100 passed their 2025 MOT first time. With 192,000 miles or more, 64 in every 100 did.

Under 116,000748 tests
75
116,000–142,000705 tests
69
142,000–165,000 Typical car764 tests
68
165,000–192,000711 tests
67
192,000 and over750 tests
64

What to check at your mileage

How often each fault turned up on a failed first test, by the car's mileage. Read it as: what is likely to need looking at on a car like the one in front of you.

Under 116,000142,000–165,000192,000 and over
Diesel engine warning light1.73.05.5
Anti-roll bar linkage pins and bushes (front)2.53.13.6
Tyre condition (rear)2.13.02.5
Individual sidelight or tail light (front)1.52.93.7
Headlight aim0.93.03.3

Faults per 100 first tests, by the car's mileage at the test.

When a car fails

30in every 100

of failed cars had one item to fix.

43in every 100

of failed cars had three or more items to fix.

8in every 100

of all first tests had a defect the tester marked dangerous (unsafe to drive away).

Every figure here is a first-attempt MOT rate from DVSA open data for this model line, for cars of this model year tested in 2025. Each mileage band holds a fifth of the tests. MOTs do not test engine or gearbox internals, so this is a pre-purchase checklist, not a full reliability score.

FAQs

Short answers about how to read this model-year guide.

The 2009 Audi A6 follows the pattern of the model years either side. Its main cause of failure was Diesel engine warning light, about 11 in every 100 failed tests. In 2025, 68.6% of 3,678 first MOTs on the 2009 Audi A6 passed first time (PRS: items fixed at the station the same day, counted as a fail). The official-style rate including PRS is 75.9%. Among 1,155 failed first-attempt MOT tests (test year 2025), Anti-roll bar linkage pins and bushes (front) appears more often than on similar cars (10.0% of those tests; 115 observed failures; about 41× more often than similar cars). There is no single reliability score here; this is a pre-purchase checklist built from DVSA open data, not a guarantee for any individual car.
Ranked by how often they were actually recorded, the items that most often failed a 2009 Audi A6 at the first attempt were Diesel engine warning light (11.2%), Anti-roll bar linkage pins and bushes (front) (10.0%) and Tyre condition (rear) (8.8%), each as a share of the year's failed first attempts. That is what goes wrong most often on the car. The common faults table shows a different measure: faults that are unusual compared with similar cars.
Among failed first-attempt tests we highlight patterns that appear more often than on similar cars. Top example: Anti-roll bar linkage pins and bushes (front) (10.0% of those tests; 115 observed failures; about 41× more often than similar cars). These are statistical signals, not a diagnosis of any individual car.
Anti-roll bar linkage pins and bushes (front) shows up more often than on similar cars (10.0% of those tests; 115 observed failures; about 41× more often than similar cars). That does not prove a design fault. Age, mileage, and how the car was used still matter. Treat it as a pre-purchase checkpoint, not a manufacturer service bulletin.
Common MOT problem areas for the 2009 Audi A6 include Anti-roll bar linkage pins and bushes (front), Seat belt condition (rear), Suspension sub-frame (front). These are the faults that stand out compared with similar cars, not a complete list of what can go wrong on any individual car.
Advisories flag issues noted at the test and are not a fail rate. We show advisory patterns that appear more often than on similar cars among failed first-attempt tests, separate from common failure rows. Use them as early-warning checks, not as a pass/fail score.
This page highlights MOT failure patterns for the 2009 Audi A6 (registration year) using UK DVSA open data for the selected test year. Patterns are compared with cars of a similar age and mileage. It is a buyer checklist from MOT defect statistics, not a full service history or manufacturer service-bulletin list.
No. MOT tests do not cover engine internals, gearboxes, or many electronic modules. Patterns here come from MOT defect statistics only and should not be read as engine or gearbox reliability scores.

About this data

How this page is built and what it can (and can't) say.

These figures come from UK MOT open data for this model year. We surface common failure patterns against similar cars, not a full reliability score, and not a pass/fail verdict on any individual vehicle.

2024 2025

What we include

UK Class 4 cars only. Normal MOT tests (not retests); first test per vehicle per calendar year; results pass, PRS, or fail.

Same-day repairs

PRS means the car failed items that were fixed at the test station and then passed the same day. We count PRS as a first-attempt fail in headline rates so same-day repairs do not hide problems.

How we compare

We compare this model year with other Class 4 cars of similar age and mileage in the same test year. This model family is left out of the peer group so the car is not measured against itself.

What this does not cover

  • MOTs do not cover engine internals, gearboxes, or many electronics; this is not a full reliability score.
  • Common faults come from MOT defect stats, not manufacturer TSBs or recalls.
  • Age and mileage matching reduces, but does not remove, differences in how cars were used and maintained.
  • If the data for a car is too thin to say anything useful, we say so rather than guess.

Contains public sector information licensed under the Open Government Licence v3.0.

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