Odometer rollback: How to avoid fraud

April 03, 2024

Odometer rollback is the (fraudulent) practice of removing or changing the mileage on a vehicle. Rollback may be performed by disconnecting, resetting, or altering the odometer itself and clearing or changing the recorded mileage.

You’d be surprised how common the practice is. Even if it’s defined as fraud.

According to a 2017 FiA (Fédération Internationale de l'Automobile) report, odometer rollback fraud affects between 5 and 12% of used car sales, rising to 30 to 50% for cross-border transactions.

What is a car odometer, and why accurate mileage is important?

Odometer is an internal component that uses a computer chip and magnetic or digital sensor to measure wheel pulses. These are registered by several different components (e.g., the Dashboard Control Unit (DCU) and the data is used to calculate the distance traveled in miles or kilometers.

You usually get to see the calculations in your dashboard:

Historically, an odometer was a system of gears that caused a drum, separated into tenths of a mile or kilometer, to turn once per mile or kilometer. These drums would be numerically separated from 0 to 9 and give you the distance traveled in the dashboard.

You may think it’s a relatively new invention. But the original invention is credited to Roman engineer and architect Vitruvius, making it more than 2000 years old.

Calculating vehicle (and chariot) mileage has always been important. Which is why it’s so fraught with fraud.

Mileage is one of primary metrics to measure wear and tear on a vehicle since it’s a good measure of how much usage it has undergone since the car left the manufacturer. Many maintenance recommendations are based on mileage.

Additionally, manufacturers have a good grasp on how long a car stays reliable. Mileage is the way they perform these measurements.

It’s also widely used by insurance companies as vehicles with larger mileage will require more frequent repairs due to simple wear and tear of internal components.

As such, odometers and mileage directly influence car value, insurance costs, and maintenance schedules. No wonder, then, that some people are keen on rolling back odometers.

How does an odometer rollback work?

Odometer tampering can be performed in two different ways, depending on the technical specification of the system.

Older cars may still have a mechanical odometer, although it’s a swiftly dying breed. While they may seem cool, they were much more easy to tamper with. Disassembly and some mechanical knowledge, gears could have been reset.

There was another common practice that was used with mechanical odometers – attaching cables to a drill. If properly performed, the spinning of the drill’s motor would cause the odometer to start rolling back.

A digital odometer is harder to tamper with. Software reprogramming, at the very least, is required, and few regular maintenance tools are able to make changes to digital odometers.

Unfortunately, there’s an entire black market for digital odometer rollback, so there’re tools that are created for that express purpose.

Depending on how the process is performed, a digital vehicle’s odometer may still have recoverable data. If it’s not cleared from the ECU, the actual mileage will still be stored and inconsistent readings could indicate tampering.

Why dealers and sellers roll back odometers

There’s a simple and consistent reason for odometer fraud – profit. Low odometer mileage indicates that the vehicle is still relatively fresh, will likely require less repairs, and may cost less to insure.

All that directly converts to a better perceived value. So, while dealers may still be selling a used car, a rolled back odometer lets them sell it faster and for a higher price.

Tampering with a car’s odometer is illegal in many countries and jurisdictions, however, it does not seem to dissuade all dealers.

Unfortunately, odometer fraud is hard to detect and prove, so it’s unlikely to disappear soon. Your best bet is to learn how to spot odometer fraud to avoid getting taken advantage of.

How to detect odometer fraud

Spotting odometer fraud can take some understanding about vehicles, so if you’re not experienced, bring a friend when buying a used car.

While there’s no foolproof way to spot odometer fraud, there are some indicators that can help you assess the actual mileage.

Physical wear and tear assessment

A used car will have some signs of usage visible on it. Check in on the steering wheel, driver’s seat, pedals, gear shift and other external components. There shouldn’t be highly visible damage to any of the components if the vehicle’s mileage is below 100 000.

Additionally, check if the car mats or steering wheel cover were replaced. While replacing them just before the sale of a used car may seem like courtesy, it may also be an attempt to hide a vehicle’s mileage.

Vehicle history report

If you want to conduct your own odometer fraud investigation, request a vehicle history report that includes all service times and repairs. A repair or service record often includes odometer readings. Check for any inconsistencies between them and the reported mileage.

Additionally, inspection records will also allow you to better assess the vehicle’s worth. Dealers may sometimes attempt to hide the vehicle’s damage history to inflate the car’s value.

Look for tampering indicators

While digital odometer fraud is advanced and hard to detect without dedicated tools, mechanical ones could have some traces. Signs of odometer tampering may include loose or misaligned numbers.

For digital odometers, you’ll likely need a professional to investigate. Some dealers will only clear the numbers on the dash but leave the data in the ECU.

Consult professionals

Bringing in someone experienced and with the tools can help you detect odometer fraud. They can run various diagnostic tests and uncover tampering in various areas.

While it will cost you money, it’ll be often significantly less than any maintenance costs you’ll incur later down the road with a used car.

Further reading: Possible red flags or signs of a scam when buying a car

How to check car mileage with OBDeleven

OBD tools can help you detect a car’s true mileage as they can retrieve reports from several systems at once. If odometer fraud has been performed, these data points may not match each other properly, indicating that the system has been tampered with.

Here’s how you can do it with OBDeleven:

Connect the device to the OBD2 port.
Turn on the device.
Head over to the Live Data section.

You’ll find odometer readings from various components of the car. The dashboard odometer reading should be the highest, so if they are out of sync, it may indicate tampering.

There’s another trick you can try to verify the mileage of a used vehicle – checking the working hours of the radio. If it’s the original one, it’ll have the amount of hours it was turned on displayed.

Assume that the car was driven for 75% of the time the radio has been turned on. And retrieve the average long-term speed.

Multiply the working radio hours by 0.75 and by the average long-term speed. You will get an estimated mileage.

It’s not a perfect method since it relies on a few assumptions. But if the mileage on the dashboard and your calculations are way out of sync, you may be dealing with a rolled back odometer.

How to report odometer fraud

So, your odometer fraud investigation leads you to believe the dealership is playing tricks to inflate a used vehicle’s value. What do you do?

Since it’s an illegal activity in almost every country, odometer fraud cases should be reported to the authorities. Here’s how:

United States: Report to National Highway Traffic Safety Administration (NHTSA). They have a dedicated unit investigating odometer fraud cases and will assign criminal penalties accordingly.
United Kingdom: Report to the Trading Standards office or Action Fraud department. While the departments are not as directly tied to odometer rollback fraud, these are the usual channels.
European Union: Report to your local police or the National Consumer Protection Authorities. In many EU countries, modifying the miles registered on a vehicle is a criminal offense and can be dealt by the police.

If you live outside of these regions, it’s often best to contact your local police. The officers involved in your complaint will, at the very least, be able to direct you to the appropriate channels.

How to avoid odometer rollback fraud

While there’s never a complete guarantee that a vehicle’s odometer has never been tampered with, you can reduce the risk by picking dealerships carefully.

Licensed car dealers will have significantly stricter guidelines and requirements. They will also be a lot more helpful if you ask for vehicle history information or a test drive.

If a dealer refuses to produce history or is attempting to hide it somehow, you should be suspicious. If there hasn’t been any odometer rollback, there should be no issues in providing such information.

Finally, you can always bring an OBD2 reader with you. A short 5 minute scan could reveal false odometer readings or other forms of tampering. These readers are significantly cheaper than any of the issues that can arise from false vehicle odometer readings.

Further reading: What are possible red flags or signs of a scam when buying a car?

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Disclaimer: Advice, how-to guides, and car care tips on our blog are intended as helpful resources for general maintenance and repairs. While we strive for accuracy, the information is provided to the best of our knowledge and should be used at your own discretion and risk.

Always refer to your vehicle's owner's manual or consult a certified mechanic for specific repair details and safety procedures.