Where Our UK MOT Data Comes From
Two sources, one goal — the most accurate picture of common UK car problems.
Every page on this site combines two distinct data sources. The first is the DVSA's public MOT dataset — 559M+ anonymised tests across 20 years of UK roads, covering every car and van that's passed through the testing network since 2005. It's the most comprehensive picture of UK vehicle reliability that exists anywhere.
The second is real-world reports from UK car owners. MOT data is great for the issues a tester sees on a ramp once a year — but it can't tell us about a fault that's never failed an MOT, or a quirk that owners notice between tests. That's where the “Tell us about your problem” form comes in.
The rest of this page walks through how we turn raw DVSA records into the problem cards you see on every model and generation page — and how owner reports sit alongside them as a fourth, human signal.
The Scale: 20 Years of UK MOT Tests
A year-by-year view of every MOT test we've processed (2005 excluded — partial data). Hover a bar for the pass/fail split.
From Raw DVSA MOT Records to Common Problem Cards
Raw DVSA data isn't usable as-is. Every MOT record uses different spellings, abbreviations and trim names; faults are recorded with internal codes; and 20 years of mixed-format files have to be reconciled against today's vehicle catalogue. Six steps turn that into the problem cards you see on every model page.
Raw DVSA Data Ingestion
559M+ MOT test records from 2005–2024, covering every UK car and van.
Make & Model Normalisation
DVSA records use every possible spelling, abbreviation and trim variant for a given car. We consolidate them against a hand-curated truth list of real UK models, so a Ford Fiesta is a Ford Fiesta whether DVSA recorded it as "FIESTA", "FIESTA ZETEC 1.4" or anything else.
Generation Matching
Every vehicle placed into the correct generation (Mk1 / Mk2 / etc.) so we can show problems at the level owners actually care about — not lumped across 20 years of a model's history.
Three-Tier Classification
Every problem type categorised as Problem, Wear & Tear, or Consumable (see the next section for what those mean). Non-car items and regulatory headers excluded.
Pattern Analysis
Compare how often each problem type occurs on a specific model versus the UK average. Only patterns the data tells us are genuinely meaningful are surfaced — small-sample noise is filtered out.
Problem Cards Generated
Significant patterns surface as Problem, Wear & Tear, or Consumable cards on each model & generation page — with average mileage at failure, % of vehicles affected, and comparison to the national average.
How We Classify Every Problem
Step 4 of the pipeline above sorts every fault type into one of three tiers. The tier tells you whether the issue is a genuine red-flag concern, an expected wear item, or a routine consumable — and lets you filter the data on each model page accordingly.
Unexpected failures — corroded, leaking, fractured, seized components. Our analysis exposes recurring patterns on specific models and surfaces them as “problems” when they appear noticeably more often than the UK average.
Components that degrade over time — bushes, shock absorbers, bearings. Replaced as part of normal servicing. Promoted to a Problem when a model shows a notably higher rate than the UK average.
Routine replacement items — brake pads, tyres, wiper blades, bulbs. Expected wear during the life of any vehicle. Promoted to a Problem when a model shows a markedly higher rate than the UK average.
Regulatory & non-car items excluded
Garage errors, after-market modifications, registration plates, and non-Class-4 items are excluded from named problems. These still count in overall MOT statistics — they're simply not shown as individual problem cards, because they don't reflect the car itself.
What You'll See on a Generation Page
Every generation page surfaces problems from four distinct sources, kept separate so you can tell what's a statistical pattern from the MOT data versus an owner's real-world experience. Three of these come from the DVSA pipeline above; the fourth is the human signal from owner reports.
Recurring patterns we've identified from DVSA MOT data — faults that show up more often on a specific generation than the UK average, surfaced as known problems for that model.
Individual MOT failure observations from DVSA data that didn't cross the statistical-significance bar. Useful for context — these are real failures recorded by the testing network, just not at a frequency that would single this generation out from the UK fleet.
Tester observations recorded against passing MOT tests — items the tester flagged as future-attention even though the car still passed. Frequency can be influenced by driving style and usage patterns, so these are presented as informational rather than diagnostic.
Problems submitted by car owners via our “Tell us about your problem” form, manually moderated by a real person who reviews each submission and clusters it under a canonical problem title for that make & model. Anecdotal — not statistically promoted — but a direct signal from owners. New 2024+ generations rely on this until they accumulate real MOT data three years from registration.
Where the Problems Land: Distribution by Category
Once classified, problems are grouped into broad categories — Brakes, Suspension, Electrical, etc. This is the catalogue distribution across every car and van we cover. Click any row to see the full stats for that category, or browse all categories.
Sorted by number of Problem cards per category. Hover for the top Problem items in each.
Why You Can Trust This UK MOT Data
Four principles underpin every number on this site.
Model-Specific Comparison
We compare how often each problem type occurs on a specific car model against the UK average across all vehicles. If a model stands out on a particular issue, we highlight it.
High-Confidence Patterns Only
We only surface patterns when the data tells us they're genuinely meaningful — not random chance. Small-sample flukes don't make it onto a page.
Data-Driven, Not Guessed
Our thresholds come from the shape of the full dataset — not arbitrary numbers we picked. Every rule is reviewed so the output matches what a reasonable person would call a “common problem”.
Full DVSA Coverage
We process every UK MOT test for cars and vans across 20 years — 559M+ tests in total.
The Other Half of the Story: Owner Reports
MOT data tells us what testers find on a ramp once a year. Owners tell us everything else.
The DVSA pipeline above is rigorous — but it can only see the faults a tester writes down at MOT time. It can't tell us about the squeak that's been driving you mad for 6 months, the recurring ECU fault your dealer can't reproduce, or the design quirk that owners discuss in forums.
That's where you come in. If you've had a recurring problem with your car that other owners should know about, tell us below. Every report is reviewed by a real person before it appears on the database, clustered with similar reports under a canonical title, and shown on the relevant generation page as a green Owner Problem card. It's the only way to surface issues that MOT data misses — and the more owners contribute, the better the picture gets.
Tell Us About Your Problem
Help other car owners — report a problem and we'll add it to the database
Tell Us About Your Problem
Help other car owners — report a problem and we'll add it to the database
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Browse Common Car Problems by Make
Select a car make to see MOT failures, advisories and common car problems
Showing top 12 — search to find any of 197 makes.
FORD
75 models · 248 problems
VAUXHALL
63 models · 225 problems
VOLKSWAGEN
54 models · 214 problems
PEUGEOT
49 models · 224 problems
RENAULT
55 models · 196 problems
NISSAN
93 models · 234 problems
CITROEN
48 models · 230 problems
MERCEDES-BENZ
46 models · 206 problems
TOYOTA
87 models · 203 problems
BMW
27 models · 99 problems
FIAT
48 models · 204 problems
AUDI
29 models · 114 problems
