Mazda Cx 3 MOT Failures

An analysis of 299,502 real DVSA MOT tests on the Mazda Cx 3 — what fails, how often, and how that compares to every other car on UK roads. Generations covered: DK (2015–2021).

Where the Mazda Cx 3 fails its MOT

The single biggest MOT failure point on the Mazda Cx 3 is seat mounting fault — this model is 59 times more likely to fail on this item than the average car on UK roads. That makes it a major concern for anyone buying or owning this model. Across 299,502 MOT tests, 0.31% of all Mazda Cx 3 tests recorded this as a failure.

Other notable weak points include reflector not securely attached (25x the fleet average), front or rear fog lamp not securely attached (19x the fleet average), anti-roll bar links worn (9.1x the fleet average), and excessive wear or play in a universal joint or ... (11x the fleet average). These ratios compare the Mazda Cx 3's failure rate on each item against the national average for all cars tested — a ratio of 10x means this model fails ten times more often than a typical car.

The failures span 5 categories: Seatbelts & Airbags, Lights & Electrics, Suspension, Steering, Tyres. If you're inspecting a Mazda Cx 3 before purchase, these are the areas to focus on — and if any have been flagged as advisories on a previous MOT, they're likely to become failures in the near future.

How failures change with mileage

The Mazda Cx 3's weak points shift as the car covers more miles. Understanding these patterns helps you know what to expect — and what to budget for — at each stage of ownership.

Under 60,000 miles

At this mileage, most failures are either design-related or caused by age rather than wear. Components like bushes and drop links may not have been replaced yet, and original-fit parts can deteriorate even on low-mileage cars that spend a lot of time sitting.

For the Mazda Cx 3 specifically, the DVSA data shows the most common failures at this mileage are reflector not securely attached (25x the average) and seat mounting fault (17x). front or rear fog lamp not securely attached (16x) and excessive wear or play in a universal joint or ... (11x) also appear frequently.

60,000 to 100,000 miles

This is where routine wear items start to show up. Brake components, tyres, and exhaust parts have done serious work by this point. Cars that have been well serviced will show fewer of these failures — this mileage band is where good maintenance really separates the well-kept from the neglected.

For the Mazda Cx 3 specifically, the DVSA data shows the most common failures at this mileage are seat mounting fault (52x the average) and front or rear fog lamp not securely attached (19x). tyre has a lump, bulge or tear caused by separa... (7.8x) and tyre has a lump, bulge or tear caused by separa... also appear frequently.

The shift from reflector not securely attached at lower mileages to seat mounting fault at higher mileages is typical — early failures tend to be design or factory-related, while high-mileage failures reflect accumulated mechanical wear. A car that's been well maintained will usually dodge the worst of both.

Known issues beyond the MOT

An MOT only tests roadworthiness at a single point in time — it won't catch developing faults, intermittent problems, or issues that haven't yet reached the failure threshold. These are the issues that Mazda Cx 3 specialists and owners flag most frequently, drawn from manufacturer technical bulletins, workshop data, and verified owner reports.

Brake pipe corrosion (1.5 diesel) Dangerous

Brake pipes on 1.5 diesel variants show premature corrosion leading to MOT failures at 9.6 times the national fleet average. Affects DK; typical independent garage repair cost is £200–£350.

CV joint excessive wear (2.0 petrol) Major

The constant velocity (CV) joints on the driveshafts show excessive wear and play at unusually low mileages on 2.0 petrol variants. Affects DK; typical independent garage repair cost is £180–£280.

Fuel pump failure Major

In-tank fuel pump failures cause engine stalling and no-start conditions. Affects DK; typical independent garage repair cost is £300–£450.

Suspension joint dust cover deterioration

Rubber dust covers on suspension joints deteriorate prematurely, with MOT failures at 16.9 times the fleet average particularly affecting higher mileage examples. Affects DK; typical independent garage repair cost is £40–£80.

For the complete picture — including repair costs across independent, specialist, and dealer garages — see the full Mazda Cx 3 common problems breakdown.

What to check before buying a Mazda Cx 3

Based on the MOT failure data and known issues above, here's what to prioritise when inspecting a Mazda Cx 3:

Seatbelts & Airbags — check for seat mounting fault. Lights & Electrics — check for reflector not securely attached, front or rear fog lamp not securely attached. Suspension — check for anti-roll bar links worn.

Beyond the MOT items, ask specifically about brake pipe corrosion and cv joint excessive wear. These won't show up on a standard MOT but can be expensive to fix — repairs start from £200. A specialist pre-purchase inspection is worth the investment on this model.

Always check the car's full MOT history for patterns — recurring advisories often become failures within 12 months. And verify the service history to confirm maintenance has been kept up to schedule. Enter any reg into our free car check to see the complete picture.

MOT failure data sourced from DVSA bulk test records via data.gov.uk. Ratios compare this model's failure rate against the national fleet average. Known issues sourced from manufacturer bulletins, specialist workshops, and verified owner reports.