Your car’s dashboard contains many gauges and measurements, but the odometer reading might be the most important. This random set of numbers means more than you might be aware of.
In this guide, I show you how to read the odometer. I also explain what it means to roll back the odometer, and how you can avoid becoming a victim of this practice.
How Does the Odometer Work?
The odometer is a measurement device that shows the total distance traveled by the car. It’s found on the car’s dashboard. Two Greek words come together to form the word “odometer,” leaving us with the meaning of path and measure.
There is also a trip odometer on most cars. Unlike the standard odometer, the trip odometer is easy to reset to show how many miles were traveled during a specific time. It’s a helpful tool if you want to figure out the approximate gas mileage of your vehicle.
How to Check the Odometer Reading
Whether you have a mechanical or electronic odometer, you can read the numbers that are shown on your car’s dashboard. These numbers show how many total miles the vehicle has been driven. However, there are some ways these numbers can be messed with, giving you a false impression.
Here is more detailed information on how to check your car’s odometer, depending on whether you have a mechanical or electronic odometer:
1. Mechanical Odometer
Mechanical odometers are constructed with a few cogs. Each one represents a numerical digit. The functionality of this kind of odometer begins at the car’s transmission. There is a small gear used to change the odometer which is found attached to the transmission.
The drive cable for the speedometer is connected to this gear, with the other end reaching the instrument cluster. As the car moves, the transmission gear also turns in conjunction. The drive cable connected to it changes the digits on the odometer.
As can be seen by the illustration above, the counting begins on the right. This particular odometer shows 160,648 km. All of these numbers will reach a peak value before resetting to zero and starting again. However, the mechanical odometer numbers can often be slightly off-center, making them more difficult to read.
2. Electronic Odometer
The electronic odometer design is newer than the mechanical type. It’s a digital odometer that is run by the electrical system. While there is still a special gear measuring the mileage, there isn’t a drive cable. Instead, a magnetic sensor is used to count how often the gear turns with the transmission. The mileage is then shown by the numbers reflected on the dashboard electronically.
Electronic odometers are more accurate than mechanical ones, and they aren’t as easy to alter. If you look at the illustration above, it shows the mileage of the vehicle at 100000 km, revealed electronically.
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Why is the Odometer Reading Important?
The numbers you read on the odometer show you how many miles the vehicle has traveled. When you look at the odometer, you know how many miles are on that vehicle’s engine, transmission and other vital parts.
This measurement is important to know before you purchase a vehicle, since the mileage determines a large part of the car’s value. Vehicles are often priced according to the model year, condition and mileage. The lower the mileage, the higher the resale value typically is.
How to Calculate Fuel Economy with the Odometer
You can use the odometer to figure out the approximate fuel economy of your vehicle. Knowing what the car should be getting, you can determine if the engine is working as it should.
- When you fill-up the gas tank, reset the trip odometer.
- Drive normally until the next time you fill-up.
- At that filling session, write down the number of gallons you added and take note of the trip mileage since the last fill-up. This shows how many miles you drove for that many gallons of gas.
- You can divide the number of miles driven by the number of gallons you put in the tank. For example, if you drove 200 miles on 10 gallons of fuel, the average fuel economy was 20 mpg.
To get the most accurate reading, try to record the mileage for an entire tank of fuel. You can also perform the test several times to see a better average.
Can the Odometer Be Wrong?
It’s possible for the odometer to show the wrong measurement. If you have a mechanical odometer, you want to watch it periodically to ensure it is recording the mileage correctly. If you measure the distance you’ve driven, the odometer should accurately report it.
If the odometer isn’t working correctly – even a little – the mismeasurement can quickly add up. Let’s assume that the odometer changes too soon – again, even by a little. It won’t take long before the car is showing far more miles than what has actually been driven, leading it to lose resale value unnecessarily.
It’s possible to have the fault repaired and get back on track. If you plan to sell your car in the future, this is something you want to take care of right away.
What Does it Mean to Roll Back an Odometer?
Dishonest people aren’t afraid to roll back the odometer to make a car look like it has fewer miles than it actually has. It is much easier to roll back a mechanical odometer. While there are some hoops to jump through to get around the security system, criminals know how to make it happen with minimal effort.
It’s not impossible to roll back a digital odometer, and those who have sought out how to do it have succeeded. It is a lot harder, because the security features are more advanced, but it’s not impossible. With either type of odometer, you must be on guard against tampering and fraud.
Otherwise, you could pay more for a vehicle, assuming it’s worth a higher value than it actually is. Odometer tampering is illegal. If you realize that the odometer of a vehicle has been rolled back, you want to take legal action against the car dealer.
How to Tell if Odometer Has Been Rolled Back
Before you purchase a vehicle, you want to be sure that the odometer is accurate. The best way to do this is to run a CARFAX report on the vehicle. With this vehicle history report, you can see how many owners the car had and see the service records. With all of the reported mileage and dates, you will know very quickly if the odometer has been turned back at some point.
For example, if the CARFAX shows that in 2019 the car had 156,000 miles on it, you would know something is wrong if you are looking at it in 2022 with only 125,000 miles on the odometer. This simple step indicates that the odometer has been messed with, and you should avoid the car at all costs.
You can also physically look at the mechanical odometer to see if anything appears shady. If you see scratches around the numbers or other imperfections, this should serve as a red flag to you.
Finally, listen to your gut. If the car dealer gives you a bad feeling or doesn’t seem to care about regulations, it’s best to choose somewhere else to do business. If the deal seems too good to be true, it probably is.