At a Glance
Across 559.4M UK MOT tests, the UK-wide fail rate is 34.9%. Electrical has the most identified common problems (7,087 distinct patterns across Problem, Wear & Tear and Consumable tiers). Since 2006, the fastest-rising category is Engine (+158%). The fastest-improving is Other (-84%).
Trend rates normalise per-category failure counts by UK MOT test volume each year, so a growing number of cars on UK roads doesn't distort the signal. Read how we measure UK MOT trends →
Problems by Category
Distinct problem patterns per category across the UK vehicle fleet, split by tier
Hover a bar for the top 3 specific problems in that tier. Switch view with the sort pills below.
Sorted by number of Problem cards per category. Hover for the top Problem items in each.
20 Years of UK MOT Trends
Per-year fail rate for every category from 2006 to 2024 — which categories are getting worse, which better
Each line is that category's failures as a percentage of UK MOT tests that year, so a growing number of cars on UK roads doesn't distort the trend. For example: Engine failures are up +158% since 2006, while Other is down -84%.
Showing all categories. Click a pill to hide; double-click to isolate.
What's in each category?
Every category is made up of specific problem types — click a category to see the 20-year breakdown by volume.
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Frequently Asked Questions
Which UK car problem category is most common?
Electrical has the most identified common problems across UK cars — 7,087 distinct problem patterns (across the Problem, Wear & Tear and Consumable tiers). Across 559.4M DVSA MOT tests, the UK-wide fail rate is 34.9%.
Which category is getting worse? Which is improving?
Since 2006, Engine has seen the biggest rise in MOT fail rate (+158% from 0.7% to 1.7% of UK tests). Other has improved the most (-84% change from 2.3% to 0.4%). Use the filter pills on the trend chart above to compare any categories side-by-side across the 20-year window.
How are these categories defined?
We map each DVSA Reason-for-Rejection (RfR) item in the MOT test standard into one of 11 DVSA-tested top-level categories (Brakes, Engine, Electrical, Suspension, Transmission, Exhaust, Tyres & Wheels, Bodywork, Cooling System, Fuel System, Steering) plus an "Other" catch-all. A smaller set of user-reportable-only categories (in-car entertainment, A/C, sunroof, software, EV-specific items) hold community submissions and unlock as data arrives.
What's the difference between a "Common Problem", "Wear & Tear" and "Consumable"?
A Common Problem occurs significantly more often on a specific vehicle than the UK average, confirmed at 99% statistical confidence — a pattern we've highlighted in the data. Wear & Tear and Consumable items also occur above average but are structurally expected (brake pads, bulbs, wipers, exhausts). All three tiers are treated separately so users see the genuine outliers without them being drowned out by ordinary service items.
How was this data calculated?
DVSA publishes anonymised MOT test records under the Open Government Licence v3. We group every problem by category, classify it against UK average rates using a two-proportion z-test, and aggregate across 20 years of data. Year-on-year rates on the trend chart normalise per-category failure counts by UK MOT test volume that year.
