CV boot at the MOT: which cars fail on it most
4.9% of failed initial MOT tests in 2025 recorded this defect: 450,802 of 9,185,328. By age, it was most common on vehicles 20 years old and over (6.9%) and least common on vehicles under 3 years old (0.9%).
It is one of the 10 most common MOT failures on 91 of the 332 car models we cover. Against vehicles of the same age, it was most common on the Citroen C3 Aircross, the Vauxhall Crossland and the Peugeot 2008. On the Citroen C3 Aircross, 17.8% of failed tests had it, against 2.1% for all vehicles of the same age.
The DVSA records it as “Drive shaft joint constant velocity boot split or insecure, no longer prevents the ingress of dirt”. A failed test can have several defects.
What the MOT checks
The boot over a drive shaft's constant velocity (CV) joint is missing, split or insecure, so it no longer keeps dirt out.
The MOT inspection manual lists “A transmission shaft constant velocity joint boot missing, split or insecure so that it no longer prevents the ingress of dirt” as a major defect, so the vehicle fails. “A transmission shaft constant velocity joint boot severely deteriorated” is a minor defect, which doesn't fail the test.
Car models where it is most common
| # | Car | Share of failed tests | Against same age |
|---|---|---|---|
| 1 | Citroen C3 Aircross5,263 failed tests | 17.8%935 tests | 8.3×all: 2.1% |
| 2 | Vauxhall Crossland12,550 failed tests | 14.8%1,862 tests | 7.5×all: 2.0% |
| 3 | Peugeot 200837,596 failed tests | 23.6%8,884 tests | 6.9×all: 3.4% |
| 4 | Peugeot Horizon1,964 failed tests | 23.7%465 tests | 6.0×all: 4.0% |
| 5 | Ford Tourneo Custom2,638 failed tests | 7.5%198 tests | 5.6×all: 1.3% |
| 6 | DS 311,270 failed tests | 21.2%2,391 tests | 5.5×all: 3.9% |
| 7 | Citroen C3 Picasso1,616 failed tests | 20.8%336 tests | 5.2×all: 4.0% |
| 8 | Ford Tourneo3,642 failed tests | 17.5%638 tests | 4.8×all: 3.6% |
| 9 | Porsche Macan3,244 failed tests | 14.4%467 tests | 4.8×all: 3.0% |
| 10 | Citroen C52,835 failed tests | 12.0%340 tests | 4.5×all: 2.7% |
| 11 | Volvo V902,503 failed tests | 11.1%278 tests | 4.5×all: 2.5% |
| 12 | Citroen C4 Grand Picasso4,744 failed tests | 16.6%788 tests | 4.4×all: 3.7% |
| 13 | Polestar 21,588 failed tests | 3.8%60 tests | 4.3×all: 0.9% |
| 14 | Citroen DS332,734 failed tests | 21.1%6,896 tests | 4.1×all: 5.1% |
| 15 | Citroen C4 Cactus6,142 failed tests | 13.0%801 tests | 4.0×all: 3.3% |
Only models where this defect is one of their 10 most common MOT failures, with at least 50 failed tests, have a figure. So a model that isn't listed can still have it, just less often than its other faults. Vans, pick-ups and taxis are left out, as in our rankings. × is the model's share divided by the share for all vehicles of the same age.
How common it is by car age
- Under 3 years, first used 2023 to 20240.9% of failed tests, against 4.9% for all ages97 failed tests
- 3 to 5 years, first used 2020 to 20221.1% of failed tests, against 4.9% for all ages7,200 failed tests
- 6 to 9 years, first used 2016 to 20193.4% of failed tests, against 4.9% for all ages72,574 failed tests
- 10 to 14 years, first used 2011 to 20155.0% of failed tests, against 4.9% for all ages168,297 failed tests
- 15 to 19 years, first used 2006 to 20106.6% of failed tests, against 4.9% for all ages146,229 failed tests
- 20 years and over, first used 1985 to 20056.9% of failed tests, against 4.9% for all ages56,405 failed tests
All-vehicle figures cover vehicles first used from 1985 to 2024: 9,185,328 of the 9,193,164 failed initial tests in 2025.
How these figures are counted
These are failures recorded at initial MOT tests in 2025. Retests are not counted. A defect found on more than one wheel, lamp or joint at the same test counts once. "Same age" is the defect's share of failed tests for all vehicles first used in the same years, weighted by the model's own failed tests in each year.
An MOT checks safety and emissions on the day of the test. These figures show where a defect was recorded, not why, and not what a repair costs. Figures: DVSA anonymised MOT tests and results, 2025. Contains public sector information licensed under the Open Government Licence v3.0. What the MOT checks: MOT inspection manual: cars and passenger vehicles, GOV.UK, read 1 Nov 2026.
How we choose and rank these defectsOther body, chassis, structure faults
Share of all failed initial MOT tests in 2025.