Odometer fraud is the disconnection, resetting or alteration of a vehicle's odometer with the intent to change the number of miles indicated.Checked 2026-08-11
Odometer rollback
Disconnecting, resetting or altering an odometer so the vehicle shows fewer miles than it has travelled.
Also called: odometer fraud · mileage rollback · true mileage unknown
What it means
Definition
NHTSA defines odometer fraud as the disconnection, resetting or alteration of a vehicle's odometer with the intent to change the number of miles indicated. Federal law requires the mileage to be disclosed at transfer of ownership and requires the seller to state when that reading is not the actual mileage. When mileage cannot be certified, some states brand the title with wording such as 'true mileage unknown'.
Why a buyer cares
What it changes
Mileage is one of the few numbers a buyer treats as objective. A rolled-back or uncertifiable reading breaks the link between that number and the car's actual use.
In practice
Where you meet it
On the odometer disclosure signed at title transfer, and as a mileage brand on the title itself.
Two things that look alike
Not the same as
A disclosed odometer or cluster replacement is lawful when the reading and the discrepancy are put in writing at the time of sale.
Read next
Related terms
Where this comes from
Sources
The 'true mileage unknown' wording is state-set and not nationally standardised — cite 49 CFR 580 for the federal disclosure duty before publishing that sentence.