The picture

79% pass rate with water ingress and CV boot quirks

79.02% first-time pass from 137,512 tests sits comfortably above the UK average, and the TT's 79,489 average test mileage suggests it's still mid-life for most. CV joint boot deterioration tops the failure chart, followed by tyre tread and windscreen damage — routine across any sports car used year-round. Owner reports reveal a different layer: water ingress into the rear hatch on the Roadster, reported repeatedly from as low as 2,000 miles and persisting across multiple production years. Frameless front windows freeze solid in cold weather on the 2015 TFSI. Interior seat trim cracks within three of four panels on the S-Line and get rejected as inflicted damage by both dealer and Audi UK. The MOT pass rate is genuinely good; the interior and weather sealing reputation is not. Factor retest likelihood into your tyre and boot inspection before booking.

Top ten reasons for rejection.

01

A transmission shaft constant velocity joint boot severely deteriorated

4,831 occurrences · 3.5% of tests
02

Tyre tread depth not in accordance with the requirements

4,427 occurrences · 3.2% of tests
03

Windscreen or window damaged or seriously discoloured but not adversely affecting driver's view

3,888 occurrences · 2.8% of tests
04

A spring or spring component fractured or seriously weakened

3,436 occurrences · 2.5% of tests
05

Headlamp reflector or lens slightly defective

3,019 occurrences · 2.2% of tests
06

A lamp missing, inoperative or in the case of a multiple light source more than 1/2 not functioning

2,801 occurrences · 2.0% of tests
07

A rear registration plate lamp or light source missing or inoperative in the case of multiple lamps or light sources

2,771 occurrences · 2.0% of tests
08

A transmission shaft constant velocity joint boot missing or no longer prevents the ingress of dirt etc

2,477 occurrences · 1.8% of tests
09

A suspension joint dust cover missing or no longer prevents the ingress of dirt etc

2,186 occurrences · 1.6% of tests
10

Engine MIL illuminated indicating a malfunction

1,974 occurrences · 1.4% of tests

Counts cover Major and Dangerous defects logged at test. Advisory items excluded so this shows why a car was rejected, not just what the tester flagged in passing.

Worst-case fix budget · top 3 failures

£150–£415

If every one of this TT's most-logged Major fails hit at the same MOT, that's the real-world UK garage range. Reality is usually one or two items, not all of them. Open the estimator →

Try the calculator

Build your own retest budget.

Tools that pre-empt a retest.

Picked against this car's top failure patterns. Affiliate links to Amazon UK — we earn a small cut at no cost to you. Disclosed up-front, doesn't shape the data.

Item 01 · Amazon UK

Digital tyre-tread depth gauge

Five quid for a gauge beats £150 for a retest. UK MOT minimum is 1.6mm — most testers fail anything below 2mm to be safe.

Search Amazon UK

Item 02 · Amazon UK

Headlight restoration kit

Yellowed lenses fail the light-output test. A restoration kit lifts the haze in an afternoon for £20.

Search Amazon UK

Owner reports · Honest John

What owners actually report.

Verbatim faults logged by owners on honestjohn.co.uk over recent years. We didn't summarise — these are the words people typed in.

Recent owner-reported faults

9 Oct 2018
Report of supplying Audi dealer and AUdi UK Customer Services turning down a warranty claim for cracks in the of the plastic side trims of seats of 2015 Audi TT Roadster S-Line 230HP DSG. Attributed to inflicted damage and not covered by warranty despite 3 of the 4 trims cracked in the same place and similar cases referenced on Audi TT user forum. Case referred to The Motor Ombudsman for consideration.
10 Apr 2018
Report of problems with Approved Used 2015 Audi TT 2.0 TFSI, bought with 15k miles: F irst issue was various interior rattles which seemed untraceable. Then when the weather got cold owner found both frameless front windows would get frozen completely, meaning you can't easily open or close the doors. Most recently it's been off the road for 2-weeks due to a failed clutch, which owner was not expecting on a car with such low mileage. Audi agreed to replace under goodwill but there was a bit of mumbling about 'wear and tear', etc.
19 Oct 2016
Another report of the water ingress problem (above 6-2-2015): " Just been reading your review of the TT and I note the running report where it mentions water getting into the hatch. It's happened to me too: twice. First at ca.2000 miles / 3 months The initial symptom was the rear number plate light failing . Then distinct sloshing sounds when cornering - the tailgate was full of water. Dealership had a go at draining & sealing it, but the exact same symptoms returned within a month. After 10 days in the dealership it seems to be sealed better this time; much grovelling from the Service Dept manager.
24 Feb 2016
Report of doors of new Audi TT, bought on a PCP in Spetember 2015, proving impossible to close when the ambient temperature drops below minus 2 degrees centigrade. Can take up to 10 minutes for the car to heat up sufficiently for the doors to latch.
6 Feb 2015
Water ingress problems with HJ long term test car. Plastic trim of boot not fitted properly.

Source: honestjohn.co.uk · 5 reports indexed

Buying or keeping a TT?

Use the failure ranking as a pre-test checklist or a haggling lever. Treat the headline pass rate as a fleet-wide trend, not a guarantee on any individual car.

If you own a TT and your last MOT looked nothing like the ranked failures above, that's normal — individual cars vary widely. The ranking shows the patterns testers flag most often across the country.