Porsche 911: what fails at MOT
80,000 MOT tests on the Porsche 911 in 2024, counted. 6.7% failed at the first attempt.
The short answer
6.7% of Porsche 911 tests failed at the first attempt. Cars of the same ages averaged 27.4%, so the 911 does better than most cars its age.
It fails most often on tyres (1% of tests), lights and electrics (1% of tests) and exhaust and emissions (0.6% of tests).
By year of registration
Older cars fail more, whatever the model. So each year is shown beside the figure for all cars first used that year.
| First used | Tests | Failed first time | All cars that year | Typical mileage |
|---|---|---|---|---|
| 2021 | 4,112 | 3.6% | 10.9% | 10,700 6,400 to 16,000 |
| 2020 | 5,143 | 3.1% | 11.5% | 15,000 10,200 to 21,000 |
| 2019 | 7,694 | 3.4% | 13.4% | 19,400 13,200 to 26,500 |
| 2018 | 6,790 | 4.6% | 15.6% | 16,900 11,000 to 25,200 |
| 2017 | 5,752 | 3.3% | 18.2% | 25,300 17,500 to 33,000 |
| 2016 | 5,069 | 3.8% | 21.3% | 27,300 18,000 to 36,300 |
| 2015 | 4,556 | 3.4% | 24.4% | 32,200 20,400 to 42,900 |
| 2014 | 4,506 | 5.0% | 27.7% | 28,600 19,400 to 41,700 |
| 2013 | 3,255 | 4.8% | 30.6% | 41,200 27,100 to 55,600 |
| 2012 | 3,876 | 6.0% | 33.4% | 49,300 36,500 to 62,400 |
| 2011 | 2,333 | 5.3% | 36.1% | 41,700 27,000 to 55,600 |
| 2010 | 3,246 | 7.6% | 38.6% | 46,400 32,600 to 63,300 |
| 2009 | 2,693 | 8.8% | 39.8% | 57,300 40,400 to 73,200 |
| 2008 | 3,411 | 11.5% | 41.5% | 54,000 40,100 to 70,200 |
| 2007 | 4,573 | 12.3% | 41.5% | 62,300 43,100 to 79,000 |
| 2006 | 4,721 | 12.0% | 42.4% | 66,800 50,600 to 85,500 |
| 2005 | 4,416 | 13.7% | 42.2% | 71,900 55,100 to 87,800 |
| 2004 | 4,332 | 14.7% | 42.3% | 72,000 51,800 to 92,100 |
Green is at least three points better than other cars that year, red at least three points worse. Typical mileage is the middle reading at the test, with the range the middle half of cars fell in.
Where it fails
The share of Porsche 911 tests with at least one failure in each part of the MOT, beside what cars of the same ages average.
| Part of the test | 911 | Cars its age |
|---|---|---|
| Tyres Less than most | 1.0% | 4.2% |
| Lights and electrics Less than most | 1.0% | 7.7% |
| Exhaust and emissions Less than most | 0.6% | 2.3% |
| Brakes Less than most | 0.5% | 4.7% |
| Body and structure Less than most | 0.4% | 2.5% |
| Suspension Less than most | 0.4% | 6.1% |
| Wipers, washers and windscreen Less than most | 0.4% | 3.1% |
The parts that fail most
- Tyre0.8%
- Headlamp aim0.5%
- Exhaust emissions0.4%
- Driveshaft joint0.3%
- Tyre tread0.3%
- Brake pipes0.2%
- Number plates0.2%
- Washers0.2%
- Wipers0.2%
- Side light0.2%
Share of tests with a failure on that part.
The most common failures
- Exhaust emissions: Lambda reading after 2nd fast idle outside specified limits0.4%
- Headlamp aim: too high0.4%
- Tyre: has a cut in excess of the requirements deep enough to reach the ply or cords0.3%
- Tyre: has ply or cords exposed0.3%
- Driveshaft joint: constant velocity boot split or insecure, no longer prevents the ingress of dirt0.3%
- Tyre tread: below requirements of 1.6mm0.2%
- Number plates: does not conform to the specified requirements0.2%
- Brake pipes: excessively corroded0.2%
- Wipers: does not clear the windscreen effectively0.2%
- Side light: not working0.1%
What testers warn about
Advisories are things that passed this time but are wearing. They are the best guide to next year's bills.
- Tyre tread: worn close to legal limit/worn on edge3.3%
- Tyre: slightly damaged/cracking or perishing1.7%
- Brake pipes: corroded, covered in grease or other material1.7%
- Brake discs: worn, pitted or scored, but not seriously weakened1.6%
- Engine oil: leak, but not excessive0.7%
- Nail in tyre0.7%
- Suspension pins and bushes: pin or bush worn but not resulting in excessive movement0.5%
- Ball joint: has slight play0.4%
What these figures can't tell you
An MOT is a safety and emissions test. These figures show how often the model fails that test. They say nothing about engines, gearboxes or electronics that break between tests, and how a car has been looked after matters more than its badge. The car you are looking at has its own MOT record, and that is the one to read.
Ask before you travel
- “How much tread is left on each tyre, and how old are they?”
- “Do all the lights work, including the number plate lights and brake lights?”
- “Has it ever failed on emissions or an exhaust leak, and what was done about it?”
- “When were the brake pads and discs last changed?”
Check a Porsche 911's own MOT record
Looking at a 911? Type its registration to see every test that car has had, what it failed on and what it was warned about, free.
Where this comes from
DVSA anonymised MOT tests and results, 2024, published by the Driver and Vehicle Standards Agency. Contains public sector information licensed under the Open Government Licence v3.0. The counting is Hindsight's own.
First-attempt MOT tests of cars first used 2004 to 2021. A test counts as failed if it failed or only passed after a repair during the test. Retests are left out. Built on 13 November 2026.