48,488 tests in 2025
Porsche 911 reliability and MOT pass rate
90.8% passed first time. The 9.2% fail rate is 13.4 points better than the all-car average, on a median example 18 years old with 52,441 miles.
Pass rate
90.8%
22.6% of all cars failed; 9.2% of these did.
Fixed on the day
1.7%
Passed after a defect was put right during the visit.
Median at test
52,441 mi
18 years old.
Fail rate by age
| Age at test | Tests | Fail rate |
|---|---|---|
| 3-5 years | 5,179 | 3.3% |
| 6-9 years | 7,325 | 4.8% |
| 10-13 years | 5,620 | 5.2% |
| 14+ years | 30,279 | 12.1% |
What the 911 fails on
Share of failed tests with at least one fail item in each DVSA inspection section. A test can fail in several sections at once.
- Lamps, reflectors and electrical equipment44 dangerous33.4%
- Tyres1,092 dangerous23.5%
- Brakes230 dangerous19%
- Noise, emissions and leaks7 dangerous19%
- Suspension40 dangerous16.6%
- Body, chassis, structure18 dangerous14.6%
- Visibility1 dangerous12.2%
- Steering7 dangerous4.2%
Is the 911 getting worse?
The fail rate fell 0.6 points to 9.8% from 2022 to 2025 while the median one tested aged 3 years. Ageing alone would predict about 1.1 points, so it is holding up better than the fleet average for its age.
| Year | Tests | Median age | Fail rate | All cars | |
|---|---|---|---|---|---|
| 2022 | 48,090 | 16 | 10.4% | 22.5% | |
| 2023 | 47,835 | 17 | 10.3% | 22.8% | |
| 2024 | 39,708 | 18 | 10.7% | 23.2% | |
| 2025 | 42,602 | 19 | 9.8% | 22.6% |
Fail rate is first attempts at class 4 tests. Median age is the age of a typical 911 at its test that year, and it is the number to watch: across the whole fleet each extra year of age adds roughly 1.9 points to the fail rate, so a model whose age and fail rate rise together is simply getting older.
The exact defects that fail it
Every failure item DVSA recorded against a 911 in 2025, counted by how many tests each one appeared on.
- 1Catalyst emissions: Lambda reading after 2nd fast idle outside specified limits501 tests
- 2Joints: constant velocity boot split or insecure, no longer prevents the ingress of dirt416 tests
- 3Position lamp: not working306 tests
- 4Condition: has ply or cords exposed298 tests
- 5Condition: has a cut in excess of the requirements deep enough to reach the ply or cords293 tests
- 6Tread depth: tread depth below requirements of 1.6mm290 tests
- 7Rear fog lamp: not working245 tests
- 8Rigid brake pipes: excessively corroded243 tests
What wears out first
Advisories are the tester flagging wear that is still legal. A typical 911 collects 2.44 of them per test, and these are the ones that come up most. Treat it as the running-repairs list for the next year or two.
- 1Tread depth: tread depth below requirements of 1.6mm3,343 tests
- 2Rigid brake pipes: excessively corroded2,449 tests
- 3Brake discs: in such a condition that it is seriously weakened2,210 tests
- 4Condition: has a tear, caused by separation or partial failure of its structure1,926 tests
- 5Engine oil leaks: leaking excessively from engine1,880 tests
- 6Pins and bushes: pin or bush excessively worn751 tests
- 7Non-component advisories: Nail in tyre627 tests
- 8Ball joint: ball joint excessively worn550 tests
Questions
What is the Porsche 911 MOT pass rate?
90.8% of the 48,488 Porsche 911 first-attempt MOTs in 2025 passed. The fail rate of 9.2% compares with 22.6% across all cars. A further 1.7% passed after a defect was fixed during the test visit.
What does a Porsche 911 usually fail on?
The single most common failure is "Catalyst emissions: Lambda reading after 2nd fast idle outside specified limits", recorded on 501 failed tests, followed by "Joints: constant velocity boot split or insecure, no longer prevents the ingress of dirt" and "Position lamp: not working". By section, lamps, reflectors and electrical equipment appears in 33.4% of failures, tyres appears in 23.5% of failures, brakes appears in 19% of failures.
Does age change the odds?
Sharply. At 3 to 5 years old the fail rate was 3.3%; at 14+ years it was 12.1%. The median Porsche 911 tested in 2025 was 18 years old with 52,441 miles.
Is the Porsche 911 getting less reliable?
The fail rate fell 0.6 points to 9.8% from 2022 to 2025 while the median one tested aged 3 years. Ageing alone would predict about 1.1 points, so it is holding up better than the fleet average for its age.
First-attempt class 4 tests, 2025, from DVSA’s anonymised MOT data (OGL v3, retrieved 2026-09-12). DVSA records newer cars trim by trim; this page adds every 911 trim together. Year-on-year figures come from the same DVSA extracts for 2026 and earlier years. Full method on the pass rates hub.
DVSA has published 21 safety recalls naming the Porsche 911: Porsche 911 recalls.
Other Porsche models
Checking a particular 911?
The odds above are the model. The car in front of you has its own record: every test, every advisory, the mileage at each one.
Due a test? Find an approved MOT station near you.