Used car guide

2020 Mazda CX-30: common problems and what to check

What gets flagged at MOT on 2020 Mazda CX-30s, from 6,204 tests in 2025, plus known faults and what to look at before you buy one.

6,204MOT tests in 2025
90%pass first time (all 2020 cars: 86%)
6,500typical miles a year
1.9×the usual rate for brake discs

What stands out

Parts flagged at MOT more often on 2020 Mazda CX-30s than on all cars registered in 2020.

  • Brake discs1.9× usual
    Mazda CX-30
    17.1% All 2020 cars
    9%

    Failed outright at MOT: 0.5%, against 0.4% of all 2020 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 absorbers3.4× usual
    Mazda CX-30
    6.8% All 2020 cars
    2%

    Failed outright at MOT: 0.4%, against 0.3% of all 2020 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.

  • Wipers1.7× usual
    Mazda CX-30
    5% All 2020 cars
    2.9%

    Failed outright at MOT: 2.9%, against 1.8% of all 2020 cars. The rest were advisories or minor defects.

    Rough price £15–£60 our estimate

    At the viewing: Test the wipers and washers on every speed.

By area

The share of 2020 Mazda CX-30 MOT tests where testers flagged each area, as a fail or an advisory. Rough prices are typical independent-garage costs.

  • Brakes
    25% 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
    24% 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
    8% 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
    7% 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
    3% 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%
20218,052Brakes 22%

Where this comes from: the DVSA's anonymised results for every MOT test in Great Britain in 2025, counting tests of 2020 Mazda CX-30s registered in 2020. "Flagged" includes advisories, so it isn't the same as a fail rate. How we score