Used car guide

2021 Mazda CX-30: common problems and what to check

What gets flagged at MOT on 2021 Mazda CX-30s, from 8,052 tests in 2025, plus known faults and what to look at before you buy one.

8,052MOT tests in 2025
92%pass first time (all 2021 cars: 87%)
7,000typical miles a year
2.2×the usual rate for brake discs

What stands out

Parts flagged at MOT more often on 2021 Mazda CX-30s than on all cars registered in 2021.

  • Brake discs2.2× usual
    Mazda CX-30
    15.4% All 2021 cars
    7.1%

    Failed outright at MOT: 0.4%, against 0.3% of all 2021 cars. The rest were advisories or minor defects.

    Rough price £150–£350 our estimate

    At the viewing: Look through the wheel at the brake disc: a deep lip at the edge or heavy scoring means they're worn. Feel for judder when braking.

  • Shock absorbers5.4× usual
    Mazda CX-30
    9.1% All 2021 cars
    1.7%

    Failed outright at MOT: 0.4%, against 0.3% of all 2021 cars. The rest were advisories or minor defects.

    Rough price £200–£300 (pair, average rear to front) ClickMechanic

    At the viewing: Push down hard on each corner. It should bounce once and settle. Look for oil on the shock absorber body.

By area

The share of 2021 Mazda CX-30 MOT tests where testers flagged each area, as a fail or an advisory. Rough prices are typical independent-garage costs.

  • Brakes
    22% 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.

  • Tyres
    21% 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.

  • Suspension
    9% 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.

  • Wipers, windscreen and mirrors
    5% of testsRough price £15–£250

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

  • Seats and seatbelts
    2% of testsRough price £80–£250

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

  • 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.

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Other years

YearMOT testsMost flagged
20226,137Tyres 18%
20206,204Brakes 25%

Where this comes from: the DVSA's anonymised results for every MOT test in Great Britain in 2025, counting tests of 2021 Mazda CX-30s registered in 2021. "Flagged" includes advisories, so it isn't the same as a fail rate. How we score