How to check a used car's real mileage

Plugging a diagnostic tool into the OBD port reads the mileage stored in the car's electronics. On many models several control units keep their own counters, and a workshop can compare them: if the gearbox module remembers more kilometres than the dashboard, the case is closed. That makes a readout worth doing when you have the car in front of you.

It is not proof in the other direction. A careful manipulation updates the other modules too, and on some cars only the dashboard value is accessible at all. So treat a clean readout as the absence of one specific red flag, not as confirmation. The readout answers what the car says about itself today; it cannot answer what the car said two owners ago.

Every periodic technical inspection records the odometer reading, and so do registrations and most service visits. Those readings, collected across the car's life and put in order, form a curve that can only ever rise. Reading that curve is the whole method: a later value below an earlier one is proof of tampering, and long flat stretches or round number jumps are the softer flags worth asking about.

The catch is that the records are scattered: inspection archives, service books, and, for imported cars, registries of countries the car left years ago. A vehicle history report by VIN pulls those recorded readings together into one timeline, which is exactly the part you cannot do from the driver's seat. The preview of what we found for a specific car is free, so checking whether recorded readings exist costs nothing.

None of this needs tools or money, and it filters out the crude cases before you spend anything on the good ones.

1. Do the math a passenger car in Europe typically covers somewhere around 10,000 to 15,000 km a year. A nine year old car showing 60,000 km is not impossible, but it needs a story, and the seller should have one ready.
2. Read the wear pedal rubber, steering wheel shine, the driver's seat bolster and the gear knob all age with use. Fresh pedals on a low mileage car are a flag on their own.
3. Open the service book readings noted at services should climb smoothly toward today's display. Gaps are common; contradictions are not.
4. Ask for inspection reports the seller of an honestly described car can usually produce the last inspection report, and its recorded reading should sit below the current display.

A falling reading ends the negotiation: you no longer know the car's real condition, so either walk away or price it as a high mileage car with unknown maintenance. Odometer manipulation is a criminal offence in most EU countries, and reporting it to the registration or consumer authority costs you little and slows the fraud for the next buyer. For everything softer than proof, a gap, a flat stretch, a missing service book, make the seller resolve it with documents, not assurances, before money moves.