It is essential to know what your car’s mileage is all the time. This is, however, impossible to do if the odometer keeps malfunctioning and resetting.
Why does my odometer keep resetting?
When the trip odometer keeps resetting, chances are that the solder joints in the cluster may be dirty or corroded, leading to electrical shorting. This is not common but happens in some vehicles.
We wanted to find out what could happen to our car’s trip odometer since it kept resetting every time we switched the ignition off.
This led us to speak to some dealers and mechanics who didn’t know much about this issue. We ended up checking with a car-loving enthusiast friend who explained his findings and possible solutions to us.
Check the Cluster Out
Your odometer is registering the same mileage every time because of a malfunction. Note that most cars, if not all, will save mileage on a small chip in the instrument cluster. This chip is referred to as the EEPROM.
EEPROM is no different from another memory unit. It is prone to wear and becomes problematic when this happens.
If you repeatedly rewrite the data, the chip will either save corrupted data or fail to save new data.
This may be the reason why your trip odometer on your dash keeps resetting. Surprisingly, sometimes the correct value is displayed.
This happens when the valid value saved in the RAM (temporary storage) is sent to the EEPROM for long-term storage. Unfortunately, the provisional value (the real one) is not stored long enough.
How Does the Odometer Display or Save?
The last EEPROM value displays when the truck starts. It continuously calculates new values by adding miles to the previous value and showing the current value on the display.
It then saves the value of several miles as added to the last value, making the final value of the EEPROM when the car stops.
How Do You Fix a Malfunctioning Trip Odometer
If the odometer keeps resetting itself, it is good to have it repaired. Do this by:
Replacing the EEPROM in the Instrument Cluster
This is a complex process that requires electronic and computer know-how. The old chip needs to be de-soldered, and a new one bought the top to replace it.
Next, you must copy the old data into the new soldered chip and update everything.
If you haven’t done this before, consider letting a professional assist. The last thing you want is to break the EEPROM in the instrument cluster. What’s more, you may need special tools to do this.
Replacing the Instrument Cluster
This is an easier way of fixing the issue. It would help if you bought a new instrument cluster or got a used one that works well.
Swap the functional instrument cluster with the broken one in your car. The replaced cluster’s odometer will start reading from the wrong mileage, but it will do the subsequent counting correctly.
Note that this may not be a problem if you intend to use the car for the longest time. However, inform the buyer about the different mileage if you sell the vehicle.
You can get the right one by reading the mileage from the ECU using the OBD2 dongle. Alternatively, have experts at the workshop use a diagnostic tool to measure the exact mileage of the car.
What if the EEPROM is Worn Out?
Typically, the EEPROM will last several erase-and-write cycles, usually in 100 thousand or millions. Usually, this is enough to last at least 20 years.
Most chips exceed the lifespan, but others may not, primarily due to storage temperatures and higher operating power.
Calculations are done both based on hours traveled and the miles covered.
Resetting/ Replacing the Cluster – Is it Legal?
Many car manufacturers place the vehicle mileage on the instrument cluster instead of the car computer.
This means changing the cluster with a new one will show a lower/brand-new mileage.
The same happens when you replace it with a used car’s cluster since the mileage of that car will be transferred to the current vehicle.
Usually, the act of replacing the cluster is illegal. It should only happen with legal consent, where the car owner must complete paperwork. It is unlawful to reset the odometer in the US as this is considered a fraudulent act meant to deter car buyers into paying more for a car with less mileage when in the real sense, it has covered more.
The legal way to have the cluster replaced is to ensure you transpose the original miles from the previous cluster before you return it. This way, the correct mileage is captured, eliminating the possibility of fraud.
Can you Manipulate the Knobs?
This would be the easiest way to reset the odometer. Find the location of the knobs on the cluster instrument. Usually, this knob shows the temperature evaluations and fuel percentage remaining.
It is also possible to manipulate this knob to reset trip miles on a car. All you have to do is press and hold this knob down for a few seconds. The odometer will reset to zero miles when the fuel economy comes up.
Reassembling the Odometer
This is a straightforward task for car lovers. Get your common mechanic tools ready and remove the cluster. You may need a screwdriver set, as well as a plier.
It is possible to reset the odometer mileage value then and reassemble everything. Some manufacturers know of this trick hence why they add tamper-proof seals.
If you decide to tamper with the odometer reading, match the mileage with the vehicle’s age since this is the fastest way to get caught.
Before taking any action to fix the malfunctioning odometer, talk to experts for the right advice. Understand the legal implications.
- Odometers may keep resetting when they are worn out or dirty
- It is possible but illegal to reset the odometer
- Some people readjust the odometer to get more money for their used car.
- Obtain legal permission to reset/ replace the odometer to avoid the fraudulent tag.