Porsche 911 MOT Failure Rate & Common Faults
We analysed 49,962 MOT tests on the Porsche 911 carried out in 2023. 12% failed at the first attempt, which is well below the 29% average across all cars in the same data. Put another way, about 9 in 10 911s passed first time.
Results cover cars first registered from 1979 to 2020. Compared with other cars of the same age, 2010 models did best (91% passed, +30.9 points against the average for 13-year-old cars), while 1981 models fared worst (78%, +1.4 points). Tested cars had covered 58,026 miles on average, against 73,145 across all cars.
The most common reason for failure was lights and electrics, found on 5.0% of tests (noticeably below the 11.3% seen across all cars). The single most frequent fault was "not working", on 2.2% of tests.
- MOT tests analysed
- 49,962
- First-time pass rate
- 88%
- All cars: 71%
- Versus all cars
- +16.4 points
- Average mileage at test
- 58,026
- All cars: 73,145
Checking a particular 911?
See its own MOT history, advisories and mileage for free.
911 MOT pass rate by year
Older cars fail more often, so each year is compared with all cars of the same age. Bars above the dashed line did better than average for their age.
| First registered | Tests | Pass rate | All cars, same age | Difference | Avg mileage |
|---|---|---|---|---|---|
| 2020 | 1,554 | 95% | 88% | +7.6 points | 13,418 |
| 2019 | 2,415 | 95% | 86% | +8.3 points | 15,510 |
| 2018 | 2,218 | 94% | 84% | +9.5 points | 16,374 |
| 2017 | 1,930 | 95% | 82% | +13.0 points | 21,827 |
| 2016 | 1,728 | 95% | 79% | +16.3 points | 25,915 |
| 2015 | 1,726 | 95% | 75% | +19.3 points | 29,677 |
| 2014 | 1,575 | 94% | 72% | +22.8 points | 32,648 |
| 2013 | 1,289 | 92% | 68% | +24.2 points | 41,068 |
| 2012 | 1,573 | 92% | 66% | +25.9 points | 45,590 |
| 2011 | 1,265 | 93% | 63% | +30.1 points | 42,576 |
| 2010 | 1,735 | 91% | 60% | +30.9 points | 48,044 |
| 2009 | 1,476 | 89% | 59% | +30.3 points | 57,410 |
| 2008 | 1,893 | 88% | 57% | +30.7 points | 56,519 |
| 2007 | 2,474 | 87% | 57% | +30.4 points | 58,228 |
| 2006 | 2,833 | 85% | 56% | +29.3 points | 66,633 |
| 2005 | 2,841 | 85% | 56% | +29.0 points | 69,833 |
| 2004 | 2,440 | 83% | 56% | +26.8 points | 72,325 |
| 2003 | 2,660 | 80% | 57% | +23.4 points | 78,223 |
| 2002 | 2,415 | 82% | 58% | +24.3 points | 82,071 |
| 2001 | 1,533 | 81% | 59% | +22.2 points | 86,395 |
| 2000 | 919 | 79% | 61% | +18.4 points | 89,570 |
| 1999 | 1,253 | 80% | 62% | +17.7 points | 92,805 |
| 1998 | 1,036 | 80% | 64% | +15.9 points | 96,231 |
| 1997 | 733 | 86% | 64% | +21.5 points | 75,740 |
| 1996 | 960 | 88% | 65% | +22.8 points | 78,634 |
| 1995 | 654 | 88% | 66% | +21.8 points | 79,361 |
| 1994 | 542 | 87% | 66% | +20.1 points | 91,435 |
| 1993 | 267 | 85% | 67% | +18.2 points | 90,400 |
| 1992 | 211 | 87% | 68% | +18.7 points | 82,798 |
| 1991 | 293 | 84% | 70% | +14.4 points | 85,640 |
| 1990 | 700 | 86% | 71% | +15.2 points | 97,159 |
| 1989 | 539 | 86% | 72% | +14.2 points | 86,414 |
| 1988 | 372 | 84% | 71% | +13.5 points | 93,976 |
| 1987 | 384 | 83% | 72% | +10.8 points | 94,778 |
| 1986 | 315 | 82% | 71% | +10.8 points | 92,797 |
| 1985 | 262 | 80% | 72% | +7.6 points | 96,881 |
| 1984 | 233 | 81% | 73% | +8.5 points | 92,984 |
| 1983 | 160 | 84% | 75% | +8.8 points | 93,359 |
| 1982 | 121 | 83% | 76% | +7.8 points | 104,113 |
| 1981 | 54 | 78% | 76% | +1.4 points | 89,892 |
| 1979 | 57 | 82% | 79% | +3.5 points | 95,898 |
Why the Porsche 911 fails its MOT
The share of tests with at least one failure in each area, compared with all cars.
| Failure area | 911 | All cars |
|---|---|---|
| Lights and electrics | 5.0% | 11.3% |
| Tyres | 2.5% | 6.3% |
| Noise, emissions and leaks | 2.1% | 3.1% |
| Brakes | 2.0% | 6.8% |
| Suspension | 1.6% | 8.9% |
| Body and structure | 1.6% | 3.5% |
| Visibility | 1.5% | 4.8% |
| Number plates and VIN | 0.5% | 0.4% |
| Steering | 0.4% | 1.8% |
| Seatbelts and airbags | 0.3% | 1.0% |
Top 10 specific failure reasons
- 1not working2.2%
- 2Lambda reading after 2nd fast idle outside specified limits1.1%
- 3too high1.0%
- 4constant velocity boot split or insecure, no longer prevents the ingress of dirt0.9%
- 5tread depth below requirements of 1.6mm0.7%
- 6has ply or cords exposed0.7%
- 7excessively corroded0.7%
- 8has a cut in excess of the requirements deep enough to reach the ply or cords0.7%
- 9does not clear the windscreen effectively0.6%
- 10not working0.5%
Common 911 MOT advisories
Advisories don't cause a fail, but they show what's wearing out. On a used 911, check whether these have been dealt with. Read our guide to MOT advisories.
| Advisory | Area | Share of tests |
|---|---|---|
| tread depth below requirements of 1.6mm | Tyres | 7.4% |
| excessively corroded | Brakes | 5.8% |
| in such a condition that it is seriously weakened | Brakes | 5.3% |
| has a tear, caused by separation or partial failure of its structure | Tyres | 4.2% |
| leaking excessively from engine | Noise, emissions and leaks | 3.7% |
| ball joint excessively worn | Suspension | 1.8% |
| pin or bush excessively worn | Suspension | 1.6% |
| Nail in tyre | Non-component advisories | 1.4% |
| tread pattern not visible over the whole tread area when minimum depth required is 1.0mm | Tyres | 1.2% |
| less than 1.5 mm thick | Brakes | 1.1% |
Tips to help your 911 pass
Based on where 911s most often fail. For a full list, use our pre-MOT checklist.
Lights and electrics · 5.0% of 911 tests
Walk round every light
With a helper, check headlights on dipped and main beam, sidelights, brake lights, indicators, the rear fog light and the number plate lamp. Replace blown bulbs in pairs and make sure no lenses are cracked.
Brakes · 2.0% of 911 tests
Don't ignore brake warning signs
Grinding, squealing, a soft pedal or the car pulling to one side under braking are all worth investigating before the MOT. Check whether the last test noted worn pads or discs; if so, they may now be below the limit.
Compare with other models
Is the 911 ULEZ compliant? See the Porsche 911 ULEZ check, or view all Porsche models.
Other Porsche models
Models with similar pass rates
About this data
Based on 49,962 first MOT tests of the Porsche 911 carried out in 2023.
Source: DVSA anonymised MOT test data (contains public sector information licensed under the Open Government Licence v3.0). First attempts on cars only; “pass rate” means passing first time. Averages cover all 32,735,164 cars tested (71% passed), and years with under 50 tests are hidden.
Learn more about how our data works.
Frequently asked questions
Answers from 49,962 first MOT tests of the Porsche 911.
What is the Porsche 911 MOT failure rate?
In our data, 12% of 49,962 first MOT attempts on the Porsche 911 ended in a fail, compared with 29% for all cars.
What is the most common reason a Porsche 911 fails its MOT?
The most common failure areas were lights and electrics (5.0% of tests), tyres (2.5% of tests), noise, emissions and leaks (2.1% of tests).
Which 911 year has the best MOT pass rate?
Allowing for age, 2010 cars performed best: 91% passed first time, +30.9 points against the average for 13-year-old cars. The weakest was 1981, at 78% (+1.4 points).
How many miles had a typical Porsche 911 covered at its MOT?
The average was 58,026 miles, against 73,145 for all cars tested. 2020 cars averaged 13,418 miles and 1979 cars 95,898.
What is the most common MOT advisory on the Porsche 911?
"tread depth below requirements of 1.6mm" was recorded on 7.4% of tests, in the tyres area. 2.5% of 911s failed in that area too.
How can I check a specific 911's MOT history?
Enter its registration in our free MOT check. Across the 49,962 911s in our data, first-time pass rates ranged from 78% to 95% by year, so one car's own record says more than the average.
Related guides
- MOT · 6 min readPre-MOT checklist: 20 things to check yourself before the testTwenty quick checks, grouped by area, that you can do on your driveway in under half an hour. No tools beyond a coin and a helper needed for most.Read the guide
- MOT · 4 min readTyre tread depth and the MOT: the legal limit and how to check6.3% of cars failed their 2023 MOT on tyres. The 1.6mm legal limit, what testers look for beyond tread, and a one-minute check with a 20p coin.Read the guide
- MOT · 4 min readDashboard warning lights and the MOT: which ones mean a fail?An engine, ABS or airbag light that stays on is a major defect at the MOT, even if the car drives perfectly. Which lights testers check, and what to do first.Read the guide
Check any 911's MOT history
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