Reading the history
MOT mileage went backwards: mistake, or something to investigate?
What it means
A later test shows a lower odometer reading than an earlier one. That lower figure needs explaining. It could be a recording error, different units, a replacement instrument cluster or an altered odometer.
Don't assume the mileage has been tampered with. Readings are entered at the test station, and mistakes can happen. But don't dismiss it either. This is a question the seller needs to answer with paperwork, not reassurance.
The shape of the sequence is the most useful thing you have. One reading that drops and then rejoins the earlier trend looks different from a trend that stays low from that point on.
What could be behind it
A number was entered wrong. Ask for an invoice or service record dated close to that test showing what the mileage actually was.
Miles and kilometres got mixed up. Compare the units as well as the figures; the history records which was used.
The instrument cluster was replaced. Legitimate, and it happens on older cars. Ask for an invoice showing the date and the readings before and after.
The mileage was altered. If the figures stay unexplained, treat the advertised mileage as unverified until the seller can account for it.
Analysis of MOT records identifies recording errors, instrument replacement and tampering as the possible explanations. It doesn't tell you which one applies here, and neither does the history on its own. A reading that later rejoins the trend is a possible recording inconsistency, not proof of the cause.
What it costs
There's no standard repair or standard deduction for this, and a lower asking price is not a substitute for knowing the mileage.
If there's a genuine instrument fault, get a diagnostic and a repair quote for that. If it's a wrong MOT entry, the fix is the official correction process, not mechanical work.
For a buyer, the decision is simpler than it looks: does the paperwork support the advertised mileage? If it does, fine. If it doesn't, either the seller resolves it or you look at a car with a clearer history. A discount can't make an unverified mileage verified.
If you're buying the car
Compare the readings and the units either side of the drop, not just the latest figure.
Ask for dated service records, invoices, and any instrument-replacement paperwork.
If the seller calls it a typo, ask them to get it corrected and show you the updated official history.
If the documents disagree and nobody can account for it, leave the mileage unverified rather than accepting a confident explanation with nothing behind it.
How the reading gets there, and how it's fixed
The odometer reading is entered during the test, with checks for possible recording errors. A recorded figure is a note of what the tester saw, not a certificate of lifetime mileage.
There are two routes to correct a Great Britain MOT mileage:
- Within 28 days: take the car back to the original MOT centre. They check the odometer and update the entry to the reading at that check.
- After 28 days: apply online with evidence dated within one day of the MOT — a service receipt or the MOT invoice, for example.
Ask to see the completed correction rather than the application. Northern Ireland records are handled separately by DVA.
What this page can't tell you
The history alone can't establish true lifetime mileage, and it can't tell a recording error from tampering. It's a guide to the record, not a diagnosis.
Next
Check a car with Lemoned to see the recorded sequence in order. Also see gaps in MOT history.
Spotted an error? Email hello@lemoned.co.uk with the passage and the source that contradicts it. Please don't send personal documents.