If a car is identified to have a minor defect then it will still pass its MOT. However, any minor defects will be recorded on the car's MOT certificate as well as its online MOT record. Rules will also change for diesel cars. If your vehicle has a diesel particulate filter and if any smoke is seen to be coming out of your exhaust then this will be categorised as a major MOT defect. If your diesel particulate filter has been tampered with in any way this will also be identified as a major MOT defect- unless the owner can prove that this was done for a legitimate cause such as filter cleaning. There will be a number of new items checked during the MOT. These items include whether or not your tyres are underinflated; as well as if your brake discs are significantly worn. There will also be new checks on reversing lights, bumper condition, rear drive shafts and also prop shafts. AdBlue Systems will be tested for defects as new assessments are to be brought in for emission control equipment. Due to this, all vehicles will be inspected to ensure they do not pose a risk to the environment through fluid leaks. If your vehicle is over 40 years old then it will no longer be a legal requirement to obtain a MOT.