Guidance

Diesel vehicle emission limits

Updated 26 February 2019

This guidance was withdrawn on

This guidance was published to help MOT testers prepare for changes made to the MOT test on 20 May 2018.

The guidance is no longer current. It is not being updated.

Check the MOT inspection manual for cars and passenger vehicles or MOT inspection manual for motorcycles for the current testing standards.

Applies to England, Scotland and Wales

© Crown copyright 2019

This publication is licensed under the terms of the Open Government Licence v3.0 except where otherwise stated. To view this licence, visit nationalarchives.gov.uk/doc/open-government-licence/version/3 or write to the Information Policy Team, The National Archives, Kew, London TW9 4DU, or email: psi@nationalarchives.gov.uk.

Where we have identified any third party copyright information you will need to obtain permission from the copyright holders concerned.

This publication is available at https://www.gov.uk/government/publications/mot-changes-from-may-2018-guidance-for-mot-testers/diesel-vehicle-emission-limits

Overview

Since 20 May 2018, there have been stricter limits for emissions from diesel cars.

For vehicles first used before July 2008, you must test to which of these values is lowest:

  • the plate value (where present)
  • the default value

For vehicles first used on or after 1 July 2008, you must test to the plate value (where present). On some vehicles, this is higher than the default value.

You must also give a major fault if you:

  • can see smoke of any colour coming from the exhaust
  • find evidence that the diesel particulate filter has been tampered with

1. How to find the manufacturer’s plate value

The ‘plate value’ is the emission limit specified by the vehicle manufacturer.

You’ll find it either on the vehicle manufacturer’s plate or on a separate plate or sticker, usually in the engine compartment.

If it’s on the manufacturer’s plate, it will be a number (usually in a box) and often at the bottom-right corner of the plate.

If the plate value is on a separate plate or sticker, it should show:

  • an ‘E’ in a circle followed by a number (representing the country that granted the approval)
  • the number 24 followed by the letter ‘R’ and the approval number

The plate value will be in a box.

Less commonly, the plate value appears in the top right corner of the emissions plate after the number 24.

Example 1

In this example, the plate value is 0.52m-1.

Vehicle plate showing diesel limit

Example 2

In this example, the plate value is 1.82m-1.

Vehicle plate showing diesel limit

2. New default limit for newer vehicles

If there’s no emission value on the manufacturer’s plate, or you cannot find it, you must use the new default limits.

Vehicle first used Type Value
1. First used before July 2008 Non-turbo 2.5m-1
  Turbo 3.0m-1
2. First used on or after 1 July 2008 All diesels 1.5m-1
3. First used on or after 1 January 2014 All diesels 0.7m-1

3. Diesel smoke meters

Diesel smoke meters should have been upgraded before 20 May 2018.

Equipment manufacturers have now carried out all orders made for upgrades and replacements.

You must stop testing all vehicles immediately if your equipment has not been updated or replaced.

Check if your diesel smoke meter meets the requirements

DVSA is aware that there’s been a problem with some devices after the upgrade. For example, the entry and use of a plate value to assess the test standard. DVSA is working with individual manufacturers and the Garage Equipment Association (GEA) to investigate and resolve issues.

If your diesel smoke meter does not appear in the list, or if you have any questions about the upgrade, contact the GEA.

Back to top