MOT defect file
Mileage discrepancy
Last updated
Quick answer
A recorded odometer reading is lower than an earlier one. Check the original certificates, service invoices and the instrument history before drawing a conclusion — a fallen reading can be a data-entry error or a replaced instrument cluster, not necessarily alteration.
- Typical cost
- Verification is usually free
- DIY viability
- Straightforward
What you might notice
- A reading in the MOT history that is lower than one recorded at an earlier test
- An implausible pattern — a car averaging 12,000 miles a year that suddenly shows 2,000, or a long stretch with almost no change at all
- Wear that does not match the number: a polished steering wheel, worn pedal rubbers, a collapsed driver's seat bolster or a shiny gear knob on a supposedly low-mileage car
- A service book, cambelt sticker or old tyre invoice quoting a mileage higher than the odometer reads today
What causes it
- A keying error at the test centre — a digit dropped or transposed when the reading was entered, which is the single most common explanation
- A replaced instrument cluster, after a fault or from a donor car, restarting the count from a different figure
- A genuine misread of a dim, partially obscured or damaged display, or a reading taken in kilometres and recorded as miles
- Deliberate alteration — clocking — which is quick and cheap to do electronically and remains a real practice in parts of the trade
Advisory or failure?
DVSA does not grade this at all, because it is not a defect and there is no pass or fail attached to it. The tester records the odometer reading as it appears on the day, and the MOT record simply publishes each reading alongside its test date. Nothing in the MOT scheme compares one reading against the previous one, and a test showing a lower figure than the year before still passes or fails purely on the condition of the vehicle. What the published history gives you is a series of dated, independently recorded data points that make an inconsistency visible — which is why the record is such a useful check even though the test itself passes no judgement on it. Note also that adjusting an odometer is not in itself illegal in the UK; selling a vehicle without disclosing that it has been adjusted is. For traders the relevant rules are the unfair commercial practices provisions in Part 4 of the Digital Markets, Competition and Consumers Act 2024, which replaced the Consumer Protection from Unfair Trading Regulations 2008 in April 2025.
Can you fix it yourself?
Straightforward
You can settle this yourself in an afternoon and it costs nothing. Ask the seller for the original MOT certificates and the service book and cross-check every mileage against the online history. Old invoices are the strongest evidence available, because tyre, cambelt and servicing paperwork each carries a date and a reading, written by different people who had no reason to make them agree. Ring the garages named on those invoices — most will confirm what is on their system. If the explanation offered is a replaced instrument cluster, there should be an invoice for it, and a properly documented replacement is normally noted or plated. Where a single reading is out by a factor of ten or has an obvious transposition, a keying error is the likely answer; where the figure falls gradually across several consecutive tests, it is not.
What it costs
Checking costs nothing but your time: the MOT history is free to view, and comparing it against certificates and invoices is the whole exercise. A commercial provenance or mileage check bundled into a vehicle history report is £10 to £20 if you want a second source. Some franchised dealers will read the mileage stored in the engine and gearbox control units, which are considerably harder to alter than the instrument cluster, for the price of a short diagnostic session. Where the discrepancy turns out to be a keying error, the test centre that made it can have the record corrected through DVSA at no cost to you.
What happens if you ignore it
The practical problem with an unexplained discrepancy is that you no longer know what the car has actually done, and everything else follows from that. Service intervals become guesswork — you cannot tell whether the cambelt, a mileage-and-time item on most engines, is due or long overdue, and a belt failure on an interference engine writes off the engine. Financially, mileage is one of the largest single factors in a used car's value, so overpaying by a wide margin is easy. The discrepancy also stays attached to the vehicle in the public record, so every future buyer will ask you the same question you should be asking now. If you have already bought and can show the seller misrepresented the mileage, you have a claim against them, and a trade seller is additionally caught by the unfair commercial practices rules in the Digital Markets, Competition and Consumers Act 2024.
This is general guidance, not a diagnosis. The severity DVSA records depends on the specific fault found, so the same item can appear as an advisory on one test and a failure on another. Ask a qualified tester or mechanic to inspect the vehicle.
Has this been recorded on your car?
Check the full MOT history for any UK registration.