About 1 in 36 MOT tests, not counting retests, ends in an emissions failure, and the most common reason is not a worn-out catalytic converter or a blocked DPF. It is the engine warning light. We analysed every initial MOT test of a passenger vehicle or light goods vehicle with an engine in Great Britain in 2024 and 2025 (MOT classes 4 and 7, electric vehicles left out), 67.4 million tests in all, using DVSA’s anonymised MOT data1. Below: the models that fail on emissions most, the ones that fail most for their age, why they fail, how age changes the odds, and where in Britain the rate is highest. Find your model in the full table.
Key findings
- 1 in 36 initial MOT tests (28.0 per 1,000) failed on emissions: 1.89 million tests over the two years, about 940,000 a year. An emissions defect was part of 9.8% of all initial MOT failures.
- The engine warning light was the most common emissions reason, found in 56% of emissions failures, and in 67% of diesel ones. Readings over the limit came second (42%). Defects of the catalytic converter or DPF itself were rare: about 2 in every 100 emissions failures.
- Age matters most. Petrol vehicles failed on emissions 3.5 times per 1,000 tests at 3 years old and 71.5 times at 20. Diesels fail more when young (17.3 at 3 years, almost all on the warning light) and peak at 15 years (50.4).
- Highest rates: the Volkswagen Crafter among diesels (69.2 per 1,000) and the Volkswagen Fox among petrol models (94.3). Worst for its age: the petrol Peugeot 208, which failed on emissions 3.2 times as often as other petrol vehicles of the same age.
- Large vans fail most: 46.3 per 1,000 tests for goods vehicles of 3,000 to 3,500 kg, against 26.9 for class 4 vehicles.
- Scotland’s test stations failed 27% more vehicles on emissions than the age and fuel of the vehicles tested would predict. Dundee had the highest rate of any postcode area (1.72 times the expected rate); Sutton the lowest (0.69).
The models most likely to fail on emissions
These are the models with the most emissions failures per 1,000 initial MOT tests in 2024 and 2025, among models with at least 20,000 tests for that fuel. The last column compares each model with vehicles of the same fuel and age: 1.00 means as expected for its age, 2.00 twice as often (see how we did it).
Diesel
| Diesel model | Fails per 1,000 | Vs same age |
|---|---|---|
| Volkswagen Crafter | 69.2 | 2.63 |
| Jeep Renegade | 67.4 | 2.63 |
| Fiat Doblo | 66.6 | 2.20 |
| Ford Fiesta | 61.0 | 1.83 |
| Jaguar X-Type | 60.2 | 1.41 |
| Vauxhall Antara | 60.2 | 1.86 |
| Fiat 500X | 60.1 | 2.32 |
| Saab 9-3 | 59.4 | 1.45 |
| Seat Ibiza | 56.9 | 1.66 |
| Alfa Romeo Giulietta | 53.5 | 1.76 |
The Volkswagen Crafter van has the highest rate, and almost all of it is the engine warning light: 62.6 of its 69.2 failures per 1,000 tests involved the light. The same goes for the Jeep Renegade, Fiat 500X, Seat Ibiza and Alfa Romeo Giulietta, whose vehicles were mostly 6 to 14 years old. The diesel Ford Fiesta is different: most of its failures (47.3 per 1,000 tests) were smoke readings over the limit, and it had the highest rate of DPF-related failures of any diesel model.
Petrol
| Petrol model | Fails per 1,000 | Vs same age |
|---|---|---|
| Volkswagen Fox | 94.3 | 1.87 |
| Vauxhall Zafira | 87.4 | 2.28 |
| Rover Mini | 86.0 | 1.33 |
| Volkswagen Beetle | 84.6 | 1.78 |
| Fiat Punto | 77.3 | 1.72 |
| Subaru Impreza | 76.1 | 1.32 |
| Peugeot 206 | 74.2 | 1.19 |
| Peugeot 207 | 72.4 | 1.53 |
| Vauxhall Vectra | 70.1 | 1.16 |
| Citroen DS3 | 67.7 | 2.13 |
Most petrol models near the top are older designs whose vehicles are now mostly 15 years old or more, such as the Volkswagen Fox and Beetle, the Peugeot 206 and 207, and the classic Rover Mini. The Vauxhall Zafira stands out: its rate is also more than twice what its age would predict.
The models that fail most for their age
A high rate can simply mean an old fleet. These lists put each model against vehicles of the same fuel and age, so the models here fail on emissions more often than their age explains.
Petrol
| Petrol model | Fails per 1,000 | Vs same age |
|---|---|---|
| Peugeot 208 | 61.4 | 3.24 |
| Smart Forfour | 48.3 | 2.62 |
| Peugeot 308 | 61.0 | 2.46 |
| Peugeot 2008 | 29.6 | 2.43 |
| Vauxhall Zafira | 87.4 | 2.28 |
| MG ZS | 17.0 | 2.14 |
| Citroen DS3 | 67.7 | 2.13 |
| Hyundai Tucson | 18.3 | 1.88 |
| Volkswagen Fox | 94.3 | 1.87 |
| Vauxhall Insignia | 46.7 | 1.81 |
Three Peugeot models are in the top four. The petrol Peugeot 208, tested 333,990 times, failed on emissions 61.4 times per 1,000 tests, 3.24 times the rate for petrol vehicles of the same age; most of its tests were at 6 to 9 years old. Its failures were mainly readings over the limit (45.2 per 1,000 tests).
Diesel
| Diesel model | Fails per 1,000 | Vs same age |
|---|---|---|
| Volkswagen Crafter | 69.2 | 2.63 |
| Jeep Renegade | 67.4 | 2.63 |
| Fiat 500X | 60.1 | 2.32 |
| Fiat Doblo | 66.6 | 2.20 |
| Mercedes-Benz Sprinter | 52.2 | 1.94 |
| Vauxhall Antara | 60.2 | 1.86 |
| Ford Fiesta | 61.0 | 1.83 |
| Nissan Navara | 50.8 | 1.83 |
| Ford Transit Courier | 42.8 | 1.82 |
| Citroen Relay | 48.9 | 1.80 |
At the other end, some models failed far less often than their age would predict: among petrol models the Mazda CX-3 (0.15), Suzuki Celerio (0.18) and Mazda CX-5 (0.20); among diesels the Volvo XC70 (0.21), BMW 4 Series (0.25) and Hyundai ix35 (0.26). The two most-tested models differ: the petrol Ford Fiesta (2.4 million tests) failed about as often as its age predicts (0.98), the petrol Vauxhall Corsa (1.7 million) 1.44 times as often.
Why vehicles fail on emissions
The MOT’s emissions checks are in section 8.2 of the inspection manual3. This is how often each reason appeared, per 1,000 initial tests. A test can fail for more than one reason, so the rows add up to more than the total.
| Reason (MOT manual 8.2) | Petrol | Diesel |
|---|---|---|
| Engine warning light on or not working | 13.5 | 19.9 |
| Gas or smoke readings over the limit | 15.3 | 8.9 |
| Exhaust or induction leak that could affect emissions | 3.0 | 0.6 |
| Particulate filter (DPF, or GPF on petrol): smoke, tampering, missing or defective | 0.0 | 0.9 |
| Visible smoke seen by the tester | 0.4 | 0.5 |
| Catalytic converter missing, modified or defective | 0.2 | 0.0 |
| Oxygen or NOx sensor, EGR valve or other equipment | 0.1 | 0.2 |
| Any emissions failure | 28.9 | 29.6 |
- The engine warning light must come on and then go out. A light that stays on, or does not work, is a major defect on petrol vehicles first used from 1 July 2003 (with up to 8 passenger seats) and on diesels first used from 1 July 20083. It was the reason in 1,064,517 failed tests over the two years. The MOT records only that the light was on, not the fault behind it.
- Readings over the limit are carbon monoxide, hydrocarbons or lambda on a petrol engine, and smoke opacity on a diesel3. They were the most common reason for petrol vehicles (15.3 per 1,000 tests).
- DPF failures were 0.9 per 1,000 diesel tests (25,806 tests in two years). Two thirds of them (17,083) were visible smoke from a vehicle fitted with a DPF, which is a fail in its own right; 6,325 involved evidence of tampering and 3,435 a DPF missing, modified or obviously defective (a test can have more than one). The diesel Ford Fiesta (4.0 per 1,000 tests), Peugeot Bipper (3.9), Mazda 6 (3.9) and Fiat Doblo (3.8) had the highest rates.
- Catalytic converter failures, a converter missing, obviously modified or obviously defective, were 0.15 per 1,000 petrol tests (5,444 tests). The Subaru Impreza was the clear outlier at 6.9 per 1,000 tests, about 15 times the rate for petrol vehicles of its age.
Age: the biggest factor
Emissions failures per 1,000 initial tests, by the vehicle’s age at the test:
| Age at test | Petrol | Diesel |
|---|---|---|
| Up to 5 years | 4.7 | 19.9 |
| 6 to 9 years | 16.8 | 25.7 |
| 10 to 14 years | 34.5 | 32.8 |
| 15 to 19 years | 59.8 | 44.8 |
| 20 years or more | 64.6 | 26.8 |
Petrol vehicles rarely fail on emissions when young: 3.5 times per 1,000 tests at 3 years old, rising to 49.1 at 15 and 71.5 at 20. Diesels start higher, 17.3 per 1,000 at 3 years old, and 16.0 of those 17.3 were the warning light. Their rate peaks at 15 years (50.4) and then falls. One reason is the rule itself: the warning-light check applies only to diesels first used from 1 July 20083, so most diesels over about 16 years old in 2024 and 2025 were not checked for it.
Vans
Goods vehicles of 3,000 to 3,500 kg (MOT class 7, the largest vans) failed on emissions 46.3 times per 1,000 initial tests, against 26.9 for class 4 vehicles. Among the most-tested vans, the Ford Transit failed 41.6 times per 1,000 tests (1.43 times the rate for diesels of its age), the Volkswagen Transporter 33.7 (1.14) and the Ford Transit Custom, a younger fleet, 12.0 (0.57).
Where in Britain
These figures are by the postcode area of the test station, not of the owner. The last column compares each area with what the age and fuel of the vehicles tested there would predict, so an area with older vehicles is not penalised for that.
Highest
| Postcode area (test station) | Fails per 1,000 | Vs same age and fuel |
|---|---|---|
| Dundee (DD) | 41.8 | 1.72 |
| Kirkcaldy (KY) | 39.7 | 1.57 |
| Lerwick (ZE) | 34.2 | 1.45 |
| Kirkwall (KW) | 37.4 | 1.36 |
| Aberdeen (AB) | 32.5 | 1.35 |
| Perth (PH) | 32.2 | 1.31 |
| Bristol (BS) | 38.1 | 1.30 |
| Falkirk (FK) | 29.6 | 1.29 |
| Paisley (PA) | 29.7 | 1.27 |
| Brighton (BN) | 37.7 | 1.25 |
Lowest
| Postcode area (test station) | Fails per 1,000 | Vs same age and fuel |
|---|---|---|
| Sutton (SM) | 20.9 | 0.69 |
| Croydon (CR) | 20.3 | 0.73 |
| Southend-on-Sea (SS) | 21.8 | 0.75 |
| Kingston upon Thames (KT) | 20.7 | 0.75 |
| Birmingham (B) | 21.5 | 0.75 |
| Enfield (EN) | 21.0 | 0.76 |
| Blackburn (BB) | 21.0 | 0.76 |
| Twickenham (TW) | 21.3 | 0.77 |
| Slough (SL) | 22.3 | 0.77 |
| Southall (UB) | 22.8 | 0.79 |
Taken together, test stations in Scotland’s postcode areas failed vehicles on emissions 30.4 times per 1,000 tests, 1.27 times the rate their vehicles’ age and fuel would predict; those in the five Welsh postcode areas 1.17 times; the rest of Great Britain 0.97. In Scotland, failures for a leak that could affect emissions were more than twice the expected rate. The data cannot say why areas differ: use, climate, roads and how tests are carried out could all play a part.
2024 and 2025 compared
The overall rate barely moved: 28.1 emissions failures per 1,000 initial tests in 2024 and 27.9 in 2025. Diesels went up, from 29.2 to 30.1, with warning-light failures rising from 19.3 to 20.6 per 1,000 tests. Petrol vehicles went down, from 29.2 to 28.7.
Every model: the full table
All 407 petrol and diesel models with at least 20,000 initial tests in 2024 and 2025. Select a column heading to sort. “Vs same age” compares the model with vehicles of the same fuel and age (1.00 = as expected). “Main reason” is the most common emissions reason for that model: the engine warning light, readings over the limit, a leak, smoke, the DPF or the catalytic converter. Each name links to the parts we list for that make or model.
| Vehicle | Fuel | Tests | Fails per 1,000 | Vs same age | Main reason |
|---|---|---|---|---|---|
| Volkswagen Fox | petrol | 49,407 | 94.3 | 1.87 | readings |
| Vauxhall Zafira | petrol | 247,688 | 87.4 | 2.28 | warning light |
| Rover Mini | petrol | 21,888 | 86.0 | 1.33 | readings |
| Volkswagen Beetle | petrol | 63,707 | 84.6 | 1.78 | warning light |
| Fiat Punto | petrol | 103,091 | 77.3 | 1.72 | readings |
| Subaru Impreza | petrol | 34,748 | 76.1 | 1.32 | readings |
| Peugeot 206 | petrol | 64,073 | 74.2 | 1.19 | readings |
| Peugeot 207 | petrol | 162,652 | 72.4 | 1.53 | readings |
| Vauxhall Vectra | petrol | 33,883 | 70.1 | 1.16 | readings |
| Volkswagen Crafter | diesel | 133,322 | 69.2 | 2.63 | warning light |
| Citroen DS3 | petrol | 70,419 | 67.7 | 2.13 | readings |
| Jeep Renegade | diesel | 27,522 | 67.4 | 2.63 | warning light |
| Fiat Doblo | diesel | 73,560 | 66.6 | 2.20 | warning light |
| Honda Accord | petrol | 29,896 | 64.4 | 1.10 | readings |
| BMW Z3 | petrol | 22,856 | 62.6 | 0.97 | readings |
| Hyundai Getz | petrol | 34,712 | 62.1 | 1.02 | readings |
| Toyota RAV4 | petrol | 64,810 | 61.6 | 1.10 | readings |
| Peugeot 208 | petrol | 333,990 | 61.4 | 3.24 | readings |
| Ford Fiesta | diesel | 345,208 | 61.0 | 1.83 | readings |
| Peugeot 308 | petrol | 88,257 | 61.0 | 2.46 | readings |
| Jaguar X-Type | diesel | 28,180 | 60.2 | 1.41 | readings |
| Vauxhall Antara | diesel | 38,407 | 60.2 | 1.86 | readings |
| Fiat 500X | diesel | 21,400 | 60.1 | 2.32 | warning light |
| Saab 9-3 | diesel | 30,992 | 59.4 | 1.45 | readings |
| Volvo V70 | petrol | 24,097 | 59.0 | 0.95 | warning light |
| Suzuki Grand Vitara | petrol | 29,609 | 57.8 | 1.08 | readings |
| Subaru Forester | petrol | 20,122 | 57.5 | 1.37 | warning light |
| Seat Ibiza | diesel | 34,244 | 56.9 | 1.66 | warning light |
| Ford Mondeo | petrol | 69,797 | 56.3 | 1.16 | warning light |
| Alfa Romeo Giulietta | diesel | 24,445 | 53.5 | 1.76 | warning light |
| Mercedes-Benz Sprinter | diesel | 425,570 | 52.2 | 1.94 | warning light |
| Nissan Almera | petrol | 25,195 | 51.8 | 0.83 | readings |
| Renault Twingo | petrol | 48,753 | 51.1 | 1.58 | readings |
| Nissan Navara | diesel | 146,319 | 50.8 | 1.83 | warning light |
| Smart Fortwo Coupe | petrol | 30,334 | 50.6 | 1.02 | warning light |
| Vauxhall Meriva | petrol | 142,503 | 50.1 | 1.36 | warning light |
| Citroen Nemo | diesel | 24,560 | 49.8 | 1.52 | warning light |
| Alfa Romeo Mito | petrol | 31,396 | 49.6 | 1.45 | readings |
| Vauxhall Vivaro | diesel | 458,176 | 49.5 | 1.73 | warning light |
| London Taxis International TX4 | diesel | 22,042 | 49.3 | 1.60 | warning light |
| Citroen Relay | diesel | 133,843 | 48.9 | 1.80 | warning light |
| Peugeot Bipper | diesel | 36,605 | 48.9 | 1.53 | warning light |
| Suzuki Jimny | petrol | 47,459 | 48.6 | 1.11 | readings |
| Smart Forfour | petrol | 43,790 | 48.3 | 2.62 | readings |
| Vauxhall Astra | petrol | 860,212 | 48.2 | 1.37 | warning light |
| Renault Trafic | diesel | 254,506 | 47.9 | 1.68 | warning light |
| Volkswagen Polo | diesel | 92,934 | 47.9 | 1.39 | warning light |
| Jaguar XJ | petrol | 22,002 | 47.6 | 0.78 | warning light |
| Ford Fusion | petrol | 76,502 | 47.4 | 0.85 | warning light |
| Peugeot 107 | petrol | 220,811 | 47.4 | 1.08 | readings |
| Mercedes-Benz Vito | diesel | 190,541 | 47.2 | 1.61 | warning light |
| Mitsubishi Colt | petrol | 39,280 | 46.8 | 0.90 | readings |
| Kia Rio | diesel | 37,933 | 46.7 | 1.44 | warning light |
| Vauxhall Insignia | petrol | 69,115 | 46.7 | 1.81 | warning light |
| Mercedes-Benz CLK | petrol | 43,367 | 46.5 | 0.76 | warning light |
| Nissan NV200 | diesel | 43,851 | 46.5 | 1.57 | warning light |
| Renault Grand Scenic | diesel | 29,326 | 45.7 | 1.42 | warning light |
| Peugeot 207 | diesel | 85,965 | 45.1 | 1.18 | readings |
| Toyota Yaris | diesel | 42,560 | 44.9 | 1.18 | readings |
| Vauxhall Movano | diesel | 109,402 | 44.7 | 1.61 | warning light |
| Ford Transit Connect | diesel | 327,739 | 44.5 | 1.54 | warning light |
| Peugeot 307 | petrol | 33,141 | 43.7 | 0.72 | warning light |
| Renault Kangoo | petrol | 20,502 | 43.7 | 0.80 | readings |
| Ford Transit Courier | diesel | 49,804 | 42.8 | 1.82 | warning light |
| Volkswagen Jetta | diesel | 20,468 | 42.3 | 1.15 | warning light |
| Mitsubishi Outlander | diesel | 37,787 | 42.1 | 1.34 | warning light |
| Vauxhall Corsa | diesel | 132,649 | 42.0 | 1.26 | warning light |
| Seat Altea | diesel | 20,443 | 41.9 | 1.12 | warning light |
| BMW 3 Series | petrol | 337,789 | 41.8 | 1.02 | readings |
| Ford Transit | diesel | 1,191,392 | 41.6 | 1.43 | warning light |
| Mazda MX-5 | petrol | 183,696 | 41.5 | 0.93 | readings |
| Nissan Juke | diesel | 166,333 | 41.3 | 1.43 | warning light |
| Vauxhall Combo | diesel | 202,010 | 40.9 | 1.44 | warning light |
| Vauxhall Corsa | petrol | 1,669,518 | 40.6 | 1.44 | warning light |
| Toyota Avensis | petrol | 56,047 | 40.4 | 0.80 | warning light |
| Toyota Corolla | petrol | 91,738 | 40.2 | 0.67 | warning light |
| Vauxhall Zafira | diesel | 127,036 | 40.2 | 1.23 | warning light |
| Renault Master | diesel | 141,937 | 40.0 | 1.35 | warning light |
| Porsche Boxster | petrol | 64,644 | 39.6 | 0.81 | readings |
| Nissan Note | diesel | 40,836 | 39.3 | 1.19 | warning light |
| Nissan X-Trail | petrol | 30,710 | 39.2 | 1.78 | readings |
| Mini (hatch) | petrol | 1,102,545 | 39.0 | 1.32 | readings |
| Honda CR-V | petrol | 178,039 | 38.8 | 0.97 | warning light |
| Volkswagen Polo | petrol | 1,172,406 | 38.8 | 1.34 | readings |
| Citroen C1 | petrol | 329,713 | 38.6 | 1.24 | readings |
| Iveco Daily | diesel | 76,001 | 38.5 | 1.34 | warning light |
| Volkswagen Touran | diesel | 114,838 | 38.5 | 1.12 | warning light |
| Saab 9-3 | petrol | 39,354 | 38.4 | 0.65 | warning light |
| Citroen Berlingo | petrol | 21,565 | 38.3 | 0.96 | warning light |
| Skoda Fabia | diesel | 86,383 | 38.3 | 1.08 | warning light |
| Citroen C4 | petrol | 67,518 | 37.9 | 1.52 | readings |
| Mercedes-Benz ML | diesel | 56,560 | 37.8 | 1.08 | warning light |
| Citroen Xsara | petrol | 27,485 | 37.7 | 0.64 | warning light |
| Volkswagen Caddy | diesel | 290,248 | 37.7 | 1.25 | warning light |
| Volvo V40 | diesel | 123,889 | 37.7 | 1.32 | readings |
| Mercedes-Benz C-Class | petrol | 247,375 | 37.6 | 1.09 | warning light |
| Audi TT | petrol | 187,510 | 37.5 | 0.98 | warning light |
| Mazda 3 | diesel | 28,554 | 37.3 | 1.22 | warning light |
| Toyota Hiace | diesel | 25,745 | 36.7 | 1.00 | readings |
| Volkswagen Passat | diesel | 326,584 | 36.6 | 1.15 | warning light |
| Citroen C3 | petrol | 258,152 | 36.3 | 1.43 | readings |
| Peugeot 208 | diesel | 74,158 | 36.3 | 1.24 | warning light |
| Mazda 6 | diesel | 62,128 | 36.2 | 1.22 | warning light |
| Volkswagen Scirocco | diesel | 51,208 | 36.1 | 1.14 | warning light |
| Ford Focus | diesel | 575,215 | 35.7 | 1.18 | readings |
| Peugeot Boxer | diesel | 214,395 | 35.2 | 1.27 | warning light |
| Toyota Auris | diesel | 26,375 | 34.8 | 1.00 | warning light |
| Citroen C3 | diesel | 138,929 | 34.6 | 1.07 | readings |
| Fiat 500L | diesel | 28,517 | 34.4 | 1.13 | warning light |
| Fiat Panda | petrol | 163,535 | 34.3 | 0.96 | readings |
| Ford C-Max | diesel | 109,719 | 34.3 | 1.11 | readings |
| Volvo V50 | diesel | 44,749 | 34.1 | 0.88 | readings |
| Audi A4 | diesel | 327,836 | 34.0 | 1.04 | warning light |
| Mercedes-Benz C-Class | diesel | 441,258 | 33.9 | 1.12 | warning light |
| Peugeot Partner | diesel | 290,498 | 33.9 | 1.22 | warning light |
| Vauxhall Mokka | diesel | 113,811 | 33.9 | 1.21 | warning light |
| Vauxhall Astra | diesel | 368,840 | 33.8 | 1.07 | warning light |
| Volkswagen Transporter | diesel | 650,681 | 33.7 | 1.14 | warning light |
| Citroen Dispatch | diesel | 106,884 | 33.5 | 1.22 | warning light |
| Ford Ranger | diesel | 245,874 | 33.5 | 1.31 | warning light |
| Nissan Elgrand | petrol | 26,436 | 33.5 | 0.72 | readings |
| Kia Venga | diesel | 22,707 | 33.4 | 1.10 | readings |
| Audi A3 | diesel | 395,185 | 33.1 | 1.01 | warning light |
| Smart Fortwo | petrol | 43,254 | 32.9 | 1.73 | readings |
| Volkswagen Touran | petrol | 27,122 | 32.9 | 1.23 | warning light |
| Volkswagen Scirocco | petrol | 42,227 | 32.7 | 1.00 | warning light |
| Citroen Berlingo | diesel | 350,497 | 32.6 | 1.14 | readings |
| Volvo C30 | diesel | 25,149 | 32.4 | 0.87 | readings |
| Volkswagen Amarok | diesel | 42,237 | 32.3 | 1.23 | warning light |
| Ford Focus | petrol | 1,275,782 | 32.2 | 0.96 | warning light |
| Land Rover Range Rover | petrol | 26,961 | 32.2 | 0.71 | readings |
| Nissan Qashqai | diesel | 543,134 | 32.1 | 1.10 | warning light |
| Ford Mondeo | diesel | 287,560 | 31.8 | 0.97 | warning light |
| Volkswagen Passat | petrol | 27,460 | 31.8 | 1.07 | warning light |
| Peugeot 308 | diesel | 170,499 | 31.6 | 1.02 | readings |
| Renault Megane | diesel | 107,991 | 31.6 | 0.98 | warning light |
| Mercedes-Benz B-Class | diesel | 91,447 | 31.5 | 1.03 | warning light |
| Ford Tourneo | diesel | 27,634 | 31.3 | 1.21 | readings |
| Volkswagen Golf | petrol | 896,714 | 31.0 | 1.05 | warning light |
| Ford Fusion | diesel | 22,314 | 30.9 | 0.77 | readings |
| Volkswagen Sharan | diesel | 60,163 | 30.7 | 1.09 | warning light |
| Toyota Yaris | petrol | 620,984 | 30.5 | 0.78 | warning light |
| Renault Scenic | diesel | 44,651 | 30.3 | 0.93 | warning light |
| Renault Kangoo | diesel | 79,707 | 30.1 | 0.97 | warning light |
| Volkswagen Beetle | diesel | 21,006 | 30.1 | 0.94 | warning light |
| Land Rover Discovery Sport | diesel | 206,000 | 29.8 | 1.22 | warning light |
| Skoda Octavia | diesel | 247,092 | 29.7 | 0.99 | warning light |
| Peugeot 2008 | petrol | 172,812 | 29.6 | 2.43 | readings |
| Mazda 3 | petrol | 184,894 | 29.5 | 0.99 | warning light |
| Volkswagen Golf | diesel | 829,274 | 29.5 | 0.92 | warning light |
| Ford Fiesta | petrol | 2,419,584 | 29.4 | 0.98 | readings |
| Ford Galaxy | diesel | 106,607 | 29.4 | 0.93 | warning light |
| Ford S-Max | diesel | 127,619 | 29.4 | 0.90 | readings |
| Peugeot Expert | diesel | 126,044 | 29.4 | 1.08 | warning light |
| Mercedes-Benz A-Class | diesel | 354,923 | 29.3 | 1.10 | warning light |
| Seat Leon | diesel | 146,045 | 29.3 | 0.95 | warning light |
| Skoda Fabia | petrol | 376,354 | 29.2 | 1.09 | readings |
| Nissan X-Trail | diesel | 148,525 | 29.1 | 1.00 | warning light |
| Ford C-Max | petrol | 108,215 | 28.9 | 0.83 | warning light |
| Vauxhall Insignia | diesel | 311,823 | 28.9 | 0.98 | warning light |
| Ford Tourneo Connect | diesel | 30,097 | 28.8 | 1.23 | warning light |
| Mercedes-Benz CLA | diesel | 54,757 | 28.7 | 1.13 | warning light |
| Fiat 500C | petrol | 41,543 | 28.6 | 0.96 | readings |
| Mercedes-Benz S-Class | diesel | 36,109 | 28.6 | 0.96 | warning light |
| Mercedes-Benz B-Class | petrol | 50,688 | 28.2 | 0.93 | warning light |
| Mitsubishi L200 | diesel | 169,007 | 28.1 | 0.95 | warning light |
| Toyota RAV4 | diesel | 87,282 | 28.1 | 0.82 | readings |
| Ford Grand C-Max | diesel | 51,768 | 28.0 | 0.96 | readings |
| Seat Alhambra | diesel | 52,064 | 28.0 | 1.01 | warning light |
| Volkswagen Caravelle | diesel | 32,173 | 28.0 | 0.94 | readings |
| BMW Z4 | petrol | 70,465 | 27.9 | 0.66 | warning light |
| Mercedes-Benz SLK | petrol | 84,379 | 27.9 | 0.53 | warning light |
| Citroen C5 | diesel | 27,060 | 27.5 | 0.96 | readings |
| Seat Ibiza | petrol | 350,340 | 27.3 | 1.09 | readings |
| Isuzu D-Max | diesel | 78,624 | 27.2 | 1.08 | warning light |
| Mercedes-Benz E-Class | petrol | 52,497 | 27.2 | 0.81 | warning light |
| Jaguar E-Pace | diesel | 48,217 | 26.9 | 1.24 | warning light |
| Toyota Avensis | diesel | 61,538 | 26.8 | 0.78 | warning light |
| Skoda Yeti | diesel | 84,782 | 26.7 | 0.88 | warning light |
| Mercedes-Benz CLS | diesel | 40,880 | 26.6 | 0.83 | warning light |
| Fiat Ducato | diesel | 189,432 | 26.5 | 0.85 | warning light |
| Honda Civic | petrol | 413,423 | 26.5 | 0.65 | readings |
| Citroen DS3 | diesel | 69,945 | 26.4 | 0.83 | readings |
| Mazda CX-5 | diesel | 76,076 | 26.3 | 0.99 | warning light |
| Toyota Proace | diesel | 33,321 | 26.3 | 1.16 | warning light |
| Vauxhall Mokka | petrol | 361,970 | 26.3 | 1.65 | warning light |
| Audi A6 | diesel | 219,600 | 26.2 | 0.86 | warning light |
| Audi A1 | diesel | 97,210 | 25.9 | 0.86 | warning light |
| Mercedes-Benz E-Class | diesel | 395,514 | 25.9 | 0.88 | warning light |
| Mini (hatch) | diesel | 205,538 | 25.9 | 0.81 | warning light |
| Renault Scenic | petrol | 24,475 | 25.9 | 0.52 | warning light |
| Mercedes-Benz Citan | diesel | 39,853 | 25.7 | 1.01 | warning light |
| Renault Clio | diesel | 129,361 | 25.4 | 0.83 | readings |
| Renault Megane | petrol | 90,996 | 25.2 | 0.59 | warning light |
| Bentley Continental | petrol | 21,989 | 25.1 | 0.53 | warning light |
| Citroen C4 | diesel | 226,600 | 25.1 | 0.83 | warning light |
| Nissan Micra | petrol | 472,964 | 25.1 | 0.63 | warning light |
| Ford Ka | petrol | 345,245 | 24.8 | 0.76 | readings |
| Vauxhall Adam | petrol | 117,868 | 24.6 | 1.14 | warning light |
| Skoda Superb | diesel | 95,402 | 24.4 | 0.90 | warning light |
| Vauxhall Meriva | diesel | 29,980 | 24.4 | 0.73 | warning light |
| Audi A6 | petrol | 26,620 | 24.3 | 1.02 | warning light |
| BMW 5 Series | petrol | 59,372 | 24.2 | 0.67 | readings |
| Kia Carens | diesel | 21,861 | 24.2 | 0.80 | warning light |
| Kia Picanto | petrol | 375,984 | 24.2 | 0.95 | readings |
| Renault Clio | petrol | 494,913 | 24.2 | 0.71 | readings |
| Peugeot 2008 | diesel | 87,294 | 24.1 | 0.89 | warning light |
| Audi A4 | petrol | 170,715 | 23.9 | 0.82 | warning light |
| Volkswagen Tiguan | diesel | 355,591 | 23.7 | 0.87 | warning light |
| Land Rover Range Rover Evoque | diesel | 334,626 | 23.6 | 0.91 | warning light |
| Peugeot 508 | diesel | 30,682 | 23.6 | 0.82 | warning light |
| Audi A5 | diesel | 145,400 | 23.2 | 0.77 | warning light |
| Volvo V60 | diesel | 59,330 | 23.2 | 0.84 | warning light |
| Alfa Romeo Giulietta | petrol | 25,817 | 22.9 | 0.88 | warning light |
| Audi A3 | petrol | 426,210 | 22.9 | 0.95 | warning light |
| Skoda Roomster | petrol | 22,503 | 22.8 | 0.60 | warning light |
| Fiat 500 | petrol | 658,519 | 22.7 | 0.90 | readings |
| Seat Mii | petrol | 34,736 | 22.6 | 0.94 | readings |
| Audi Q5 | diesel | 169,716 | 22.5 | 0.83 | warning light |
| BMW 1 Series | petrol | 374,670 | 22.5 | 1.03 | warning light |
| Kia Sportage | petrol | 242,033 | 22.5 | 1.76 | readings |
| Nissan Note | petrol | 258,507 | 22.5 | 0.57 | readings |
| Mercedes-Benz GLA | diesel | 86,921 | 22.3 | 0.88 | warning light |
| Ford Ecosport | diesel | 25,516 | 22.2 | 0.86 | readings |
| Peugeot 5008 | diesel | 48,640 | 22.1 | 0.84 | warning light |
| Honda Jazz | petrol | 616,491 | 21.9 | 0.59 | readings |
| Land Rover Range Rover Velar | diesel | 57,403 | 21.9 | 0.99 | warning light |
| Suzuki SX4 | petrol | 66,589 | 21.9 | 0.72 | warning light |
| Jaguar XE | diesel | 60,815 | 21.7 | 0.86 | warning light |
| Mazda 6 | petrol | 56,355 | 21.5 | 0.67 | readings |
| Toyota Verso | diesel | 22,872 | 21.5 | 0.69 | warning light |
| Volvo S60 | diesel | 25,591 | 21.3 | 0.66 | warning light |
| Volkswagen Touareg | diesel | 71,798 | 21.2 | 0.71 | warning light |
| Dacia Duster | diesel | 66,656 | 20.9 | 0.77 | warning light |
| Skoda Octavia | petrol | 149,863 | 20.6 | 1.00 | warning light |
| Suzuki Alto | petrol | 93,541 | 20.5 | 0.56 | warning light |
| Volvo V70 | diesel | 55,310 | 20.4 | 0.56 | readings |
| Abarth 595 | petrol | 37,961 | 20.3 | 1.52 | warning light |
| BMW M3 | petrol | 32,208 | 20.3 | 0.45 | readings |
| Volkswagen CC | diesel | 26,611 | 20.3 | 0.67 | warning light |
| Seat Leon | petrol | 216,018 | 20.2 | 1.08 | readings |
| Toyota Aygo | petrol | 531,400 | 20.1 | 0.80 | readings |
| Porsche Cayenne | petrol | 26,826 | 19.9 | 0.64 | warning light |
| Chevrolet Spark | petrol | 28,100 | 19.8 | 0.56 | warning light |
| Peugeot 108 | petrol | 154,158 | 19.8 | 1.22 | warning light |
| Mitsubishi Asx | diesel | 29,550 | 19.7 | 0.68 | warning light |
| Kia Ceed | petrol | 99,735 | 19.6 | 0.81 | readings |
| Toyota Hilux | diesel | 156,232 | 19.6 | 0.71 | warning light |
| Skoda Citigo | petrol | 103,876 | 19.3 | 0.88 | readings |
| Nissan Pulsar | petrol | 29,168 | 19.1 | 1.04 | warning light |
| DS DS3 | petrol | 49,090 | 18.8 | 1.28 | readings |
| BMW X3 | petrol | 28,379 | 18.7 | 1.04 | warning light |
| Toyota Estima | petrol | 20,064 | 18.6 | 0.50 | readings |
| Audi Q3 | diesel | 136,143 | 18.4 | 0.67 | warning light |
| Ford Kuga | diesel | 455,604 | 18.4 | 0.68 | warning light |
| Vauxhall Agila | petrol | 66,964 | 18.4 | 0.41 | readings |
| Ford Ecosport | petrol | 189,267 | 18.3 | 1.64 | readings |
| Hyundai Tucson | petrol | 158,158 | 18.3 | 1.88 | readings |
| Jaguar F-Pace | diesel | 92,495 | 18.3 | 0.79 | warning light |
| Mitsubishi Shogun | diesel | 48,363 | 18.3 | 0.58 | readings |
| Citroen C4 Cactus | petrol | 31,536 | 18.1 | 1.47 | readings |
| Dacia Sandero | diesel | 42,592 | 18.1 | 0.66 | warning light |
| Mercedes-Benz SL | petrol | 42,019 | 17.8 | 0.35 | readings |
| Suzuki Swift | petrol | 220,546 | 17.7 | 0.57 | warning light |
| Volkswagen up! | petrol | 251,811 | 17.6 | 0.79 | readings |
| Nissan Qashqai | petrol | 559,381 | 17.5 | 0.79 | warning light |
| Toyota Land Cruiser | diesel | 35,006 | 17.5 | 0.57 | readings |
| Toyota Auris | petrol | 133,987 | 17.4 | 0.43 | warning light |
| Kia Sorento | diesel | 65,225 | 17.3 | 0.57 | warning light |
| Honda Civic | diesel | 120,979 | 17.2 | 0.52 | warning light |
| Audi Q7 | diesel | 91,865 | 17.1 | 0.59 | warning light |
| Mazda 2 | petrol | 247,733 | 17.1 | 0.58 | warning light |
| Peugeot 3008 | diesel | 184,345 | 17.1 | 0.61 | warning light |
| MG ZS | petrol | 76,265 | 17.0 | 2.14 | readings |
| Renault Kadjar | diesel | 68,412 | 16.9 | 0.67 | warning light |
| Skoda Kodiaq | diesel | 36,272 | 16.9 | 0.77 | warning light |
| Hyundai i30 | diesel | 94,339 | 16.8 | 0.55 | warning light |
| Nissan Juke | petrol | 473,572 | 16.7 | 0.86 | readings |
| Toyota iQ | petrol | 33,551 | 16.7 | 0.40 | readings |
| BMW 1 Series | diesel | 420,119 | 16.6 | 0.53 | warning light |
| Audi TT | diesel | 37,866 | 16.5 | 0.51 | warning light |
| Dacia Sandero | petrol | 177,444 | 16.4 | 1.13 | warning light |
| Fiat 500X | petrol | 51,338 | 16.4 | 1.22 | readings |
| Hyundai i20 | petrol | 235,263 | 16.4 | 0.64 | warning light |
| Suzuki Ignis | petrol | 36,615 | 16.4 | 0.58 | warning light |
| Suzuki Splash | petrol | 33,759 | 16.4 | 0.42 | readings |
| Ford B-Max | petrol | 91,110 | 16.3 | 0.63 | readings |
| Mercedes-Benz GLC | diesel | 123,789 | 16.2 | 0.70 | warning light |
| Porsche 911 | petrol | 102,897 | 16.2 | 0.37 | readings |
| BMW 2 Series | diesel | 94,989 | 16.1 | 0.64 | warning light |
| Porsche Cayenne | diesel | 25,149 | 16.0 | 0.53 | warning light |
| Volvo XC60 | diesel | 167,432 | 16.0 | 0.57 | warning light |
| Jeep Renegade | petrol | 29,086 | 15.8 | 1.19 | warning light |
| Renault Captur | diesel | 129,974 | 15.8 | 0.59 | warning light |
| Hyundai i40 | diesel | 40,430 | 15.7 | 0.55 | warning light |
| Land Rover Range Rover Sport | petrol | 29,908 | 15.5 | 0.79 | warning light |
| Porsche Cayman | petrol | 29,108 | 15.5 | 0.47 | readings |
| Land Rover Defender | diesel | 232,118 | 15.4 | 0.51 | readings |
| Mini Countryman | diesel | 53,818 | 15.4 | 0.55 | warning light |
| BMW X6 | diesel | 26,554 | 15.3 | 0.53 | warning light |
| Jaguar XF | diesel | 173,261 | 15.2 | 0.49 | warning light |
| Land Rover Discovery | diesel | 298,628 | 15.2 | 0.50 | warning light |
| Hyundai i10 | petrol | 498,059 | 15.0 | 0.59 | warning light |
| BMW 3 Series | diesel | 544,927 | 14.9 | 0.47 | warning light |
| Kia Rio | petrol | 156,101 | 14.9 | 0.60 | warning light |
| Nissan Pixo | petrol | 22,254 | 14.9 | 0.36 | readings |
| Mercedes-Benz A-Class | petrol | 335,954 | 14.7 | 0.78 | warning light |
| Audi A5 | petrol | 106,984 | 14.6 | 0.68 | warning light |
| Peugeot 3008 | petrol | 89,999 | 14.5 | 1.28 | readings |
| Honda CR-V | diesel | 183,827 | 14.4 | 0.43 | warning light |
| Volkswagen T-Roc | diesel | 26,709 | 14.4 | 0.68 | warning light |
| Kia Optima | diesel | 20,296 | 14.3 | 0.56 | warning light |
| Vauxhall Viva | petrol | 76,527 | 14.3 | 0.92 | warning light |
| Audi A7 | diesel | 29,840 | 13.9 | 0.50 | warning light |
| Hyundai i30 | petrol | 110,402 | 13.8 | 0.49 | readings |
| BMW 5 Series | diesel | 305,873 | 13.7 | 0.44 | warning light |
| Mercedes-Benz CLA | petrol | 76,503 | 13.7 | 1.26 | warning light |
| Mercedes-Benz V-Class | diesel | 26,659 | 13.7 | 0.59 | warning light |
| Hyundai Santa Fe | diesel | 61,149 | 13.6 | 0.44 | warning light |
| Land Rover Range Rover Sport | diesel | 202,576 | 13.4 | 0.44 | warning light |
| Land Rover Freelander | diesel | 223,292 | 13.3 | 0.36 | readings |
| Kia Ceed | diesel | 140,253 | 13.1 | 0.44 | warning light |
| Vauxhall Grandland | diesel | 30,504 | 13.1 | 0.61 | warning light |
| BMW X5 | diesel | 142,079 | 12.7 | 0.41 | warning light |
| BMW X3 | diesel | 156,515 | 12.5 | 0.43 | warning light |
| Ford Mustang | petrol | 25,000 | 12.4 | 0.59 | readings |
| BMW 7 Series | diesel | 24,256 | 12.2 | 0.40 | warning light |
| Seat Ateca | diesel | 24,595 | 12.2 | 0.53 | warning light |
| BMW X4 | diesel | 27,255 | 12.1 | 0.49 | warning light |
| Ford Kuga | petrol | 113,758 | 12.0 | 1.03 | readings |
| Ford Transit Custom | diesel | 391,767 | 12.0 | 0.57 | warning light |
| Mercedes-Benz SLK | diesel | 26,472 | 11.9 | 0.39 | warning light |
| Mitsubishi Asx | petrol | 28,693 | 11.9 | 0.60 | readings |
| Audi A1 | petrol | 361,630 | 11.8 | 0.67 | readings |
| Volvo XC40 | diesel | 22,762 | 11.8 | 0.55 | warning light |
| BMW X1 | diesel | 142,915 | 11.6 | 0.41 | warning light |
| Land Rover Range Rover | diesel | 142,669 | 11.6 | 0.38 | warning light |
| Dacia Duster | petrol | 82,448 | 11.4 | 1.39 | readings |
| Jaguar XE | petrol | 26,103 | 11.2 | 0.84 | warning light |
| Ford Tourneo Custom | diesel | 23,318 | 11.1 | 0.54 | warning light |
| Skoda Rapid | petrol | 30,132 | 11.1 | 0.51 | readings |
| Hyundai Tucson | diesel | 99,595 | 10.9 | 0.41 | warning light |
| Jaguar XJ | diesel | 23,664 | 10.9 | 0.33 | warning light |
| Kia Sportage | diesel | 289,009 | 10.7 | 0.38 | warning light |
| Peugeot 5008 | petrol | 24,236 | 10.3 | 1.29 | warning light |
| Mercedes-Benz GLA | petrol | 86,823 | 10.1 | 1.13 | warning light |
| Kia Soul | diesel | 28,364 | 9.9 | 0.32 | warning light |
| Mercedes-Benz GLE | diesel | 53,829 | 9.9 | 0.43 | warning light |
| Vauxhall Crossland | petrol | 134,393 | 9.9 | 1.48 | readings |
| Volvo XC90 | diesel | 98,278 | 9.8 | 0.31 | warning light |
| Volkswagen California | diesel | 21,770 | 9.7 | 0.38 | warning light |
| Volvo V40 | petrol | 72,270 | 9.4 | 0.52 | warning light |
| Skoda Yeti | petrol | 65,793 | 9.1 | 0.39 | warning light |
| BMW 6 Series | diesel | 27,700 | 8.9 | 0.30 | warning light |
| MG 3 | petrol | 46,061 | 8.8 | 0.70 | warning light |
| Jaguar F-Type | petrol | 30,479 | 8.7 | 0.51 | warning light |
| Renault Kadjar | petrol | 69,938 | 8.7 | 0.88 | warning light |
| Audi Q3 | petrol | 133,479 | 8.5 | 0.71 | readings |
| Citroen C3 Aircross | petrol | 61,519 | 8.1 | 1.03 | readings |
| Hyundai ix35 | diesel | 85,727 | 8.0 | 0.26 | warning light |
| Mini Clubman | petrol | 37,565 | 8.0 | 0.50 | warning light |
| BMW 2 Series | petrol | 154,518 | 7.9 | 0.70 | warning light |
| Toyota Verso | petrol | 31,735 | 7.7 | 0.26 | warning light |
| Audi Q2 | diesel | 31,781 | 7.5 | 0.34 | warning light |
| Land Rover Range Rover Evoque | petrol | 25,523 | 7.4 | 0.76 | warning light |
| Volvo XC70 | diesel | 32,509 | 7.4 | 0.21 | warning light |
| Hyundai Kona | petrol | 36,218 | 7.3 | 0.86 | warning light |
| Mitsubishi Mirage | petrol | 22,423 | 7.3 | 0.36 | readings |
| Audi Q5 | petrol | 49,482 | 7.2 | 0.54 | warning light |
| Honda HR-V | petrol | 46,344 | 7.0 | 0.45 | readings |
| Skoda Karoq | diesel | 26,184 | 6.9 | 0.32 | warning light |
| BMW 4 Series | diesel | 126,547 | 6.7 | 0.25 | warning light |
| Mini Countryman | petrol | 134,925 | 6.7 | 0.51 | warning light |
| BMW M4 | petrol | 26,103 | 6.6 | 0.48 | readings |
| Mercedes-Benz GLC | petrol | 23,993 | 6.6 | 0.68 | warning light |
| Skoda Superb | petrol | 28,700 | 6.6 | 0.48 | warning light |
| Volvo V90 | diesel | 20,390 | 6.6 | 0.28 | warning light |
| Kia Venga | petrol | 70,953 | 6.0 | 0.26 | warning light |
| Citroen C5 | petrol | 20,593 | 5.7 | 0.72 | warning light |
| Hyundai ix20 | petrol | 50,578 | 5.7 | 0.24 | warning light |
| Vauxhall Grandland | petrol | 110,831 | 5.6 | 0.80 | warning light |
| Kia Stonic | petrol | 35,790 | 5.4 | 0.66 | warning light |
| MG HS Exclusive | petrol | 25,491 | 5.4 | 1.14 | warning light |
| Renault Captur | petrol | 182,280 | 5.4 | 0.41 | readings |
| Volkswagen Tiguan | petrol | 140,035 | 5.4 | 0.65 | warning light |
| BMW 4 Series | petrol | 82,318 | 5.1 | 0.37 | warning light |
| Mazda CX-30 | petrol | 35,421 | 5.0 | 1.07 | warning light |
| Seat Arona | petrol | 97,637 | 4.8 | 0.70 | warning light |
| Ford Puma | petrol | 151,031 | 4.6 | 0.74 | warning light |
| Skoda Kodiaq | petrol | 45,854 | 4.6 | 0.59 | warning light |
| Suzuki Vitara | petrol | 104,925 | 4.4 | 0.31 | readings |
| Skoda Kamiq | petrol | 40,433 | 4.3 | 0.91 | warning light |
| Volvo XC60 | petrol | 22,695 | 4.3 | 0.40 | warning light |
| Seat Ateca | petrol | 75,155 | 4.0 | 0.45 | warning light |
| Volkswagen T-Cross | petrol | 54,031 | 3.9 | 0.78 | warning light |
| BMW X1 | petrol | 68,335 | 3.7 | 0.39 | warning light |
| Mitsubishi Eclipse | petrol | 24,308 | 3.5 | 0.36 | warning light |
| Skoda Karoq | petrol | 88,314 | 3.5 | 0.53 | warning light |
| Volkswagen T-Roc | petrol | 143,226 | 3.4 | 0.52 | warning light |
| Volvo XC40 | petrol | 78,849 | 3.3 | 0.57 | warning light |
| BMW X2 | petrol | 21,992 | 3.1 | 0.49 | warning light |
| Kia Xceed | petrol | 33,304 | 3.1 | 0.65 | warning light |
| Suzuki Celerio | petrol | 54,837 | 3.0 | 0.18 | readings |
| Audi Q2 | petrol | 126,714 | 2.7 | 0.31 | warning light |
| Porsche Macan | petrol | 47,912 | 2.2 | 0.22 | warning light |
| Mazda CX-5 | petrol | 63,351 | 2.0 | 0.20 | readings |
| Mazda CX-3 | petrol | 44,952 | 1.9 | 0.15 | readings |
If your vehicle fails on emissions
The failure document names the defect, and the emissions printout gives the readings. What to do depends on which of the reasons above it was:
- Engine warning light. The MOT records only that the light was on or not working, not why. Have the fault code read first. A code such as P0420 points at the catalytic converter’s efficiency, but the cause is often elsewhere: see our P0420 guide. On Renault, Dacia, Peugeot and Citroën vehicles the message may read “check anti-pollution system”: see what that warning means.
- Readings over the limit or visible smoke. Our guide to failing the MOT on emissions explains what high CO, high HC, a lambda reading or a smoke reading points to, and what to fix before buying any part. If the tester saw smoke, its colour is the clue: see what white, blue or black exhaust smoke means.
- A leak that could affect emissions. Fix the leak first, then retest: see exhaust leaks and the MOT.
- DPF faults. Our DPF fault codes guide covers the common codes, and whether DPF cleaning works covers the options short of a new filter.
- A catalytic converter or DPF that needs replacing. For most vehicles first used from 1 March 2001, a business may only supply or fit a replacement catalytic converter that is type approved for that vehicle, and the same rule covers DPFs on vehicles built to Euro 5 and Euro 64. You can find the parts listed for your vehicle with our vehicle search, in catalytic converters or in DPFs.
How we did it
We used DVSA’s anonymised MOT data, the record of every MOT test carried out in Great Britain, published as open data under the Open Government Licence1. It holds no registration numbers or VINs, and neither does anything we publish. We used the 2024 and 2025 test results and failure-item extracts that DVSA added on 22 June 2026.
- Which tests. Initial MOT tests (DVSA’s “normal test”, so retests are left out) of class 4 vehicles (passenger vehicles with up to 8 passenger seats, and goods vehicles up to 3,000 kg) and class 7 vehicles (goods vehicles over 3,000 kg up to 3,500 kg), with a result of pass, fail or “pass after rectification at the station”. This is how DVSA counts initial failure rates2.
- What counts as an emissions failure. A test with at least one defect recorded as a fail, or as a fail put right at the station within the hour, under section 8.2 “Exhaust emissions” of the MOT inspection manual3: emission control equipment (catalytic converter, DPF, oxygen or NOx sensor, EGR valve) missing, obviously modified or obviously defective; gas or smoke readings over the limit; visible smoke; evidence of DPF tampering; an exhaust or induction leak that could affect emissions; and the engine warning light. That is 98 of DVSA’s reasons for rejection. “Emissions test unable to be completed” is not counted, and neither is a major exhaust leak found when the exhaust system itself is inspected (a separate section of the test).
- Rates are per 1,000 initial tests. Fully electric vehicles have no exhaust and are left out of every rate. Hybrids are shown separately: their fuel type is not always recorded reliably2, and they are not smoke-tested3.
- Age is the vehicle’s age at the test, in whole years from its date of first use.
- Models. DVSA records model names as entered, so trim names were folded into the base model (for example “Focus Zetec” into Ford Focus, “320d” into BMW 3 Series), and the Mini hatch’s names (Mini, Cooper, One) were merged. A model is ranked only if it had at least 20,000 initial tests over the two years with that fuel, which keeps its rate to within about 2 per 1,000.
- “Vs same age” divides a model’s emissions failures by the number expected if it had failed at the national rate for vehicles of the same fuel and age group (up to 5, 6 to 9, 10 to 14, 15 to 19, and 20 years or more). 1.00 means as expected for its age; 2.00 means twice as often. It does not adjust for mileage or use.
- Areas are the postcode areas of the test stations, not of the owners. Areas with fewer than 20,000 tests are not ranked.
- Checks. Our quarterly totals for classes 3 and 4 match DVSA’s published MOT statistics5 to within 0.4% on the number of tests and 0.01 percentage points on the initial failure rate and on the share failing for “noise, emissions and leaks”, in seven of the eight quarters. In the eighth, July to September 2025, DVSA’s published figures repeat those for April to June; our count for that quarter (8.63 million tests) is in line with July to September 2024 (8.65 million).
Using this data
You are welcome to quote these figures with a link to this page. Download the data (CSV): by make and model, by age at test and fuel and by postcode area. The list of DVSA codes we counted is available from our contact page. Contains public sector information licensed under the Open Government Licence v3.06.
Sources (accessed 31 October 2026)
- Driver and Vehicle Standards Agency, “MOT Anonymised Data”: MOT testing data results extracts and failure item extracts, 2024 and 2025 (added 22 June 2026), with the item detail and item group extracts. open.data.dvsa.gov.uk
- DVSA, “MOT testing data user guide” (post-May 2018), v5.1: dataset specification, test types and outcomes, and how DVSA calculates initial failure rates. open.data.dvsa.gov.uk
- DVSA, MOT inspection manual for private passenger and light commercial vehicles, section 8: Nuisance (8.2 Exhaust emissions), updated 14 October 2026. gov.uk
- The Motor Vehicles (Replacement of Catalytic Converters and Pollution Control Devices) Regulations 2009 (SI 2009/1899), regulations 2 and 4 to 7. legislation.gov.uk
- DVSA, “MOT testing data for Great Britain”: test results by class of vehicle, and initial failures by defect category for classes 3 and 4 and class 7. gov.uk
- The National Archives, Open Government Licence v3.0. nationalarchives.gov.uk
