MOT: Diesel fails up 240%

29 January 2021  

A record 1.27 million vehicles failed their MOT in the 2019/2020 period due to emissions, with diesels seeing a 240% failure rise compared to just 37% for petrol vehicles.

Via a Freedom of Information (FOI) request to the DVSA, price comparison site BookMyGarage showed that more cars have failed on emissions in the last two years than any other.

In May 2018, MOT regulations intended to cut down on excessive emissions came in, which has led to the rise. Overall failures last year were up by more than 70% compared to 2017/2018– the final year before the new rules applied. Meanwhile, DVSA also introduced new fault categories, with ‘Major’ or ‘Dangerous’ faults resulting in a failed test. Almost all petrol emissions failures were classed as ‘Major’ last year. By comparison, around 5% of all diesel emissions failures were classed as ‘Dangerous’.

Jessica Potts, Head of Marketing at BookMyGarage.com said: “The regulations have mostly impacted diesel cars, causing more than triple the number to fail, compared to petrol car failures which have only increased by a third.

“The large increase in diesel failures was caused by a change to rules for cars equipped with a DPF. Any car equipped with a DPF will fail a MOT if there is either evidence it has been tampered with or if smoke of any colour can be seen coming from the exhaust.”

 Jessica added: “What this data tells us though, is that an increasing number of relatively modern diesels are struggling to pass the MOT test as their emissions control systems face tougher scrutiny. It’s important these systems function correctly to protect the environment, but putting them right can also cost owners thousands of pounds.”   To see an interactive graph comparing annual data for MOT emissions failures visit https://bookmygarage.com/blog/mot-failures-due-to-emission