A “True Mileage Unknown,” or TMU vehicle has an odometer reading that is inaccurate. Dealers will “Roll back” odometers to increase the value of a vehicle. A 30,000 mile car has much less mechanical wear and tear than a 100,000 mile car. Digital odometers can be rolled back in a few minutes using a computer. Mechanical odometers can be manually rolled back. If a odometer roll-back is detected, the DMV will brand the title to the vehicle “TMU.” This greatly decreases the value of a vehicle because it is impossible to know how much it has been used.

Many insurance companies will refuse to insure a TMU vehicle. Many banks will refuse to finance loans to buy a TMU vehicle.