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What has happened?

BMW, along with 4 other major car manufacturers has been accused of colluding to deploy defective emissions control strategies in their diesel vehicles over an eight-year period. In addition, it is alleged that BMW group utilise so-called ‘thermal windows’ to reduce the effectiveness of vehicles’ emissions controls when driven on the roads. The KBA (the German vehicle regulator) has ordered a number of vehicles to be recalled as a result of the use of unlawful defeat devices.

The allegations add to the question marks surrounding BMW’s purported commitment to clean diesel. In 2017 an independent study found that certain BMW models exceeded regulatory NOx limits by more than 7 times. In addition, a study by Transport and Environment, a clean air campaign group, found that when tested the BMW 5 Series, 4 Series, and X3 showed results indicating the presence of thermal windows, a form of defeat device. In defence of thermal windows some manufacturers have suggested that they are necessary to protect various engine components. However, following the CJEU judgment it is likely this will amount to an unlawful defeat device. Read about the CJEU decision here.

In addition, the environmental organisation Deutsche Umwelthilfe, tested a BMW 320d diesel and found that the car appeared to turn off emissions control systems when it reached a certain number of revolutions, often at the level that would be expected in normal use, and in low gears.

Click here to read further about emissions claims

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The scandal in numbers


estimated number of ‘dirty’ BMW diesels on European roads


BMWs recalled for faulty emissions software


excess deaths caused by air pollution each year

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Can I join?

The following models have been particularly implicated:

750d xDrive
750Ld xDrive
2 Series GT 216d
4 Series 420d

However, anybody who bought a diesel BMW in vehicle in England or Wales manufactured between 2009 and 2018 can apply to join the claim. If you bought or leased an affected vehicle in Scotland or Northern Ireland, you can still join a claim, but it will be handled slightly differently.

The litigation will be free at the point of use. Harcus Parker will act on a no-win, no-fee basis, and will pay any third-party costs which are necessary in order to progress the claims to trial.


NOx contains both Nitrogen Oxide and Nitrogen Dioxide. NOx is emitted when fossil fuels are burnt, but not completely combusted. Diesel engines are not 100% efficient, meaning that their exhaust emissions contain NOx, as well as greenhouse gases such as carbon dioxide and carbon monoxide, and air pollutants such as particulate matter. NOx worsens air quality and has adverse health effects including contributing to respiratory problems and cancer. Diesel cars are one of the main causes of pollution in our air.

These allow cars to turn down their emissions control system outside the emissions testing environment i.e. when the cars are driven in the real world. Not all defeat devices are cheating devices – some are allowed by regulations. However, in many cases they are used by manufacturers to give the appearance that their diesel vehicles pass emissions tests, when in fact they do not.

The term used to describe the emissions scandal which broke when the German car maker, VW, admitted to fitting more than 11 million of their VW cars with unlawful defeat devices leading to the first major emissions class action lawsuit in the United States.

We use this term to cover both owners of cars, and people who leased their cars.

A senior court of England and Wales dealing with high value and high importance non-criminal matters. This court ruled that it will be bound by findings of the KBA (the German motor authority) that defeat devices are present.