Why Did My Car Mileage Reset? Explanation and Concerns

Your car mileage could reset because you are using Trip A or Trip B, you've changed the dashboard, or there is a problem with the ECU. Also, it can be a glitch in the electronics of your vehicle. In this article, I will explain each of the possible versions and give advice on what you can do to get things back in order.

Dash electrical problems highlights

• Level of urgency:low
• DIY inspection:impossible
• DIY repair:impossible
• Can you drive?yes
• Price for repairs:$250 - $550
• Symptoms:glitchy dash, functions not working, no lights, no data
• Ways to solve:try disconnecting the battery for some time, take it to a professional

Possible reasons for car mileage reset in your vehicle

First of all, we need to discuss the issues that could trigger this problem. I should tell you that this is not really a common issue that drivers have to deal with. So, you aren't likely to find a lot of information on the internet. But still, I've spoken to car mechanics and to dealership workers to try and find all the possible reasons for such a phenomenon.

Let's see what can cause this issue:

1. You are using Trip A or Trip B meter

Almost every car has several mileage meters. One of them is overall car mileage and this is the default monitor in your car. But then, there may be one or two additional meters that you can reset to zero whenever you want. In older types of dashes, the additional mileage was presented by the second scale with miles and it was hard to mix the main one and the additional scale.

But in newer vehicles, there are two additional meters that you can use independently. Also, if you press and hold the reset button whenever this meter is on the screen, you will set it to zero again.

Here's what may have happened:

• your car is new, so the mileage is close to zero and you still don't know how to control all those functions of the dash;
• you pressed the trip mileage meter button unintentionally and your mileage monitor changed, no you see the Trip A meter;
• but since the car is new or you haven't touched this meter yet, it can show exactly the same mileage as your main odometer monitor;
• then, unintentionally, you press and hold the reset button or someone else does this in your car;
• the trip meter resets and you see zero miles instead of, for example, 5000 miles that were there yesterday;
• you start panicking and thinking that your vehicle is affected by some kind of problem and you need professional help.

Your first thought may be that now you don't know when you should change the oil in your vehicle next time. Your second thought may be even worse - can they void your warranty for messing up the mileage in your car?

All you need to do is calmly read the driver's manual and learn how to operate the available mileage meters like Trip A and Trip B. In most cases, you will see that this is the culprit of your problem. Just find out how you switch between monitors and get to the original odometer. Usually, you will do that by shortly pressing the Reset button. But there are other options, too.

2. You've changed the dash

While in the majority of vehicles, the information about the mileage is stored in the ECU and some other blocks, some older vehicles may have all the information about the odometer readings in the dashboard. Your original dash may have been faulty or affected by something like water or heat and you bought the used dash for your car on eBay or at the local scrapyard.

But after you installed the new dashboard, you suddenly saw that your mileage is not original. It may be too low or too high. It means that in your vehicle the mileage information is stored in the dashboard.

Chevy cars and some other GM models used to have this feature about 15 years ago. But when the new generation of Chevy cars started to appear on the market, the mileage information relocated to other units like the ECU or other electronic blocks.

Now you have two choices - forget about this and just drive your car, or go to the shop and set the mileage close to your original figures.

3. ECU glitch

In many vehicles, the information about mileage in your car is stored in their ECUs. These blocks may be located in different places, and sometimes their location is not very convenient. For example, they can be placed in such a way that water can come into contact with them after some seal is broken.

Or they can be placed close to heat-generating objects under the hood and overheat regularly. This can lead to issues with electronic parts in the ECU and the car's brain may eventually just be fried. This will lead to all kinds of unpleasant consequences and you will have to deal with them as soon as possible.

The car may heavily glitch, throw different error messages and warning lights, refuse to start and show different odometer figures every time you try to start it. So, this can be the reason for your problem. Unfortunately, solving this kind of problem is not that easy - in most cases, you will need the new ECU and will have to pay a lot for its adjustments.

4. Long time with no power

The mileage of the vehicle is stored in a special chip. The memory of this chip is saved when the car is out of battery power. But it won't be stored eternally. Sooner or later, the chip will be reset and will show zero mileage when you connect the battery to the car.

Also, the dying battery in the car that has been resting for 2-3 months or more can mean that your vehicle will get low voltage. When there is low voltage in the electrical system of the car, different units and modules can burn and get broken. The chips can be fried easily in such conditions, so it's worth checking whether this is something that has happened to your car.

Sometimes, you can still restore the original mileage. But in some cases, you may not know it at all and will have to deal with the problem in some other way.

How can you restore the original mileage in your car?

So, you've checked and now see that it's not the Trip A meter that reset, but it's the overall mileage of the car. The odometer shows zero miles or something like that and you want to get it back to normal.

Here's what you can try:

• Reset the ECU. You may try disconnecting the battery for 5-10 minutes and checking if this helps you with the mileage problem. Maybe, it's some glitch in the control unit and you can get rid of it that easily.
• Get the mileage in the ECU. With the help of your OBD2 scanner, you can read the original mileage of the car that is stored in the ECU, PCM, or some other modules. Then, you can use this reading to set the original mileage on the dash.
• Use professional help. You may go to a good repair shop and tell them about the problem. These guys will use professional OBD2 equipment to get the reason for the issue and also to set the original mileage back to your dash.

I don't see any other good options of what you can do to solve the problem with the zero mileage in your car.

Of course, all these methods will only work with modern electronic dashes. If you have the old dash with plastic drums and figures on them that show the mileage, you will need to buy the new odometer, manually set it to the needed mileage, and then install it into the dash.

What can go wrong if your mileage was reset?

Actually, messing up with the mileage in your car is a bad idea. First of all, you can lose the warranty coverage when this is revealed. Also, you won't be able to easily sell the car because the buyer will want to know the original mileage and see it on the dash. No one will want to buy a car with an odometer rollback.

Also, you will not know when is the next oil change due. This may be a serious problem because driving more than needed with the contaminated oil can be dangerous for the vehicle.

I strongly recommend keeping the odometer readings original. Even if you noticed that something is wrong with the odometer, you can easily go to the repair shop and have the car inspected so that you could know the reason and fix the problem.