How to Tell a Vehicle’s True Mileage — The Complete Used Car Buyer’s Guide for the USA
Buying a used vehicle is one of the biggest financial decisions most people make — and mileage is one of the most important factors in a car’s value. Unfortunately, odometer fraud remains a significant issue in the US used car market. Here’s how to protect yourself.
Why Mileage Matters So Much
A vehicle’s mileage directly affects its value, remaining lifespan, and service requirements. According to the National Highway Traffic Safety Administration (NHTSA), odometer fraud costs US consumers over $1 billion annually — with unsuspecting buyers paying inflated prices for vehicles with far more miles than shown.
Step 1 — Run a Vehicle History Report
The first step in verifying a vehicle’s mileage is running a history report through a service like CARFAX or AutoCheck. These services compile mileage data from service records, state inspections, insurance claims, and dealer submissions — creating a mileage timeline you can cross-reference against the odometer.
Red flags include: mileage decreasing between records, large unexplained gaps in mileage history, or records stopping suddenly.
Step 2 — Request a Pre-Purchase Inspection
Have a trusted mechanic perform a pre-purchase inspection (PPI) before buying. A good mechanic will look at wear patterns on the brake pedal, seat bolsters, steering wheel, and gear shift to assess whether they match the claimed mileage. High wear on a “low mileage” car is a major red flag.
Step 3 — Check the Service Records
Ask for all available service records. Oil changes, tyre rotations, and other routine services are typically logged with mileage — creating an independent record of the vehicle’s odometer history.
Step 4 — Run a Diagnostic Scan
A professional OBD diagnostic scan reads mileage data from multiple ECUs simultaneously. If the instrument cluster mileage differs from the transmission ECU or other modules, this is a clear sign of odometer tampering using a cheap device.
Step 5 — Check the Title and Odometer Disclosure
Under US federal law, sellers are required to provide an odometer disclosure statement when selling a vehicle. This must state the mileage at time of sale and whether the seller believes it to be accurate. Keep this document — it provides legal protection if you later discover odometer fraud.
Odometer Fraud Is a Federal Crime
Altering a vehicle’s odometer reading with intent to defraud a buyer is a federal offence under the Motor Vehicle Information and Cost Savings Act. Penalties include fines of up to $10,000 per violation and up to 3 years in prison.
Note on Mileage Blockers
Our CAN Bus mileage blockers are sold exclusively for dyno testing, off-road use, and private property performance evaluation. They do not alter existing odometer data and are not odometer correction tools. Misrepresenting a vehicle’s mileage when selling is illegal and something we strongly oppose.