Used car guide

2021 BMW M4: common problems and what to check

What gets flagged at MOT on 2021 BMW M4s, from 954 tests in 2025, plus known faults and what to look at before you buy one.

954MOT tests in 2025
92%pass first time (all 2021 cars: 87%)
6,100typical miles a year
17%had tyres flagged

What gets flagged at MOT

The share of 2021 BMW M4 MOT tests where testers flagged each area, as a fail or an advisory. Rough prices are typical independent-garage costs.

  • Tyres
    17% of testsRough price £70–£150

    At the viewing: Check the tread on all four tyres, including the inside edges, and look for cracks or bulges.

  • Wipers, windscreen and mirrors
    2% of testsRough price £15–£250

    At the viewing: Check for chips in the driver's view, and test the wipers and washers.

  • Lights and electrics
    2% of testsRough price £10–£80

    At the viewing: Ask a friend to check every light, including brake lights and indicators, while you operate them.

  • Brakes
    2% of testsRough price £150–£350

    At the viewing: Look for a lip on the disc edges and feel for judder or pulling when braking firmly from about 40mph.

  • Suspension
    1% of testsRough price £120–£400

    At the viewing: Listen for knocks over speed bumps, and look behind each front wheel for a snapped coil spring.

  • Seats and seatbelts
    1% of testsRough price £80–£250

    At the viewing: Pull each seatbelt sharply. It should lock, and retract cleanly.

Looking at a BMW M4?

Check the actual car: its own MOT history, mileage and what to ask the seller. Free, no sign-up.

Other years

YearMOT testsMost flagged
20221,452Tyres 18%
20201,154Tyres 20%
20191,714Tyres 20%
20181,992Tyres 21%
20171,937Tyres 21%
20161,691Tyres 21%
20151,800Tyres 21%
2014914Tyres 19%

Where this comes from: the DVSA's anonymised results for every MOT test in Great Britain in 2025, counting tests of 2021 BMW M4s registered in 2021. "Flagged" includes advisories, so it isn't the same as a fail rate. How we score