Dr Mark Peckham
March 2024

The effect of Euro 6 vehicle “defeat devices” on urban air quality

This webinar introduced the findings of recent tests done to explore the impact of "defeat devices" fitted to diesel vehicles on air pollutant emissions.

Euro 6 diesel passenger vehicles (mostly fitted with 'SCR' catalysts to reduce their NOx emissions) have been common since 2014 but their natural aging has meant that they are now starting to fail MOT tests due to SCR failures (indicated by a warning light mandated by legislation).

Legitimate repairs and replacements are expensive (typically £800+) but there is another option: the “emulator” is an SCR defeat device which disables the SCR system and suppresses the warning light, thus enabling the vehicle to pass through the current MOT.  A quick internet search for “Adblu emulator” will bring up many pages of defeat devices for trucks, vans and cars, sometimes accompanied by claims of better fuel economy but generally with a price tag of £50 or less. In the very small print, it might be possible to spot wording to the effect that: “once fitted, the vehicle should not be driven on European roads”.  Many garages who previously provided “engine re-mapping” services will also offer the fitting of defeat devices.

The results from some recent tests involving the deliberate defeating of an otherwise clean, modern diesel vehicle were shown in this webinar, turning this normally Euro 6 vehicle in to a “gross emitter”.