A car computer is one of the most important features of a car — it helps the car work smoothly and perform to its maximum.
However, sometimes the computer malfunctions. If there is a sign that something is wrong, such as an illuminated check engine light, you shouldn’t ignore it. Even though many times the only thing wrong is a simple glitch in the system, you’ll want to make sure that your car is safe to drive.
In any case, you may want to save some money and check what’s going on before you head off to see a professional. Resetting your car computer can be done at home, and it is not difficult — you just need to follow a few steps, and you’ll be done in no time.
So, here are the basics on car computers, issues they can go through, and the two methods to restart your car computer at home.

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What Does a Car Computer Do?
Every car comes with at least one car computer. It collects the info from various sensors in a vehicle, including:
- The oxygen sensor
- The air pressure and temperature sensors
- The engine temperature sensor.
Using this info, the computer controls the engine and makes your drive smoother and more pleasant. Among other things, the computer controls fuel injectors, spark plugs, idle speed, and so on. It’s there to make sure the emissions are as low as possible as well.
So, what could possibly go wrong, you ask? Well, many things. The (sort of) good news is that if your computer is experiencing some issues, there will be warning signs.
Symptoms of a Faulty Car Computer
Well, the following problems could be symptoms of a faulty car computer:
- You’re having trouble starting your car. Have you ever been late to work because your car just wouldn’t start? If there is a problem with the car computer, this is a likely scenario. If your vehicle is having any difficulties starting, check the computer ASAP.
- The check engine light is on. We’re all guilty of continually postponing the check-up when the check engine light is on. Even though it’s very easy to ignore it — don’t. It is not on without a reason, so make sure to take a careful look at your car.
- Your car is having some engine issues. It can be anything from decreased fuel economy to unpredictable engine behavior.
- There is a burning smell in your car. Never ignore the burning smell, and always check your ECM if you feel it. Heat is dangerous for your car, and it can cause all sorts of issues.
How Can Resetting the Computer Help?
Resetting your car computer helps you narrow down the possible cause. In other words, it enables you to eliminate the possibility that the issue your car is going through is just a glitch in the system. If the problem remains after the reset, you need to conduct further investigation. If it goes away, though – you’re good.
You can reset the car battery at home, without professional assistance. There are two methods; you can reset the car computer and leave the car battery on, or you can turn the battery off. Here are the instructions for both ways.
How to Reset a Car Computer With the Battery On
Here’s what you’ll need:
- a fuse puller or a pair of pliers
- a code reader.
Here is a step-by-step guide on how to do it:
- Find the vehicle’s fuse box. There should be a cover showing the info on the car’s fuses and amperage.
- Remove the cover.
- Find the fuses labeled “Back-up” and another one labeled “ECU” and pull them out.
- Leave the fuses out for 10 minutes before you reinstall them.
- Put the cover back.
- Start your vehicle and go for a test drive.
- It should start smoothly, and there should be no glitches during the drive itself. Check the check engine light – it should be off now.
How to Reset a Car Computer With the Battery Off
You can always decide to try to reset your car computer with your battery off. Before you start anything, turn off your car. Now, for this method, you’ll need:
- battery wrench or pliers
- a cable tie or insulating tape
- a 10-watt resistor
- some water and baking soda.
When you have everything, here’s what you’ll do.
- Remove the battery terminals with the help of the wrench or pliers.
- Remove the battery. Removal of the battery breaks the circuit, so the power can’t flow into the engine.
- Tie the negative and positive wires together with insulating tape or cable tie. Leave them for 45 minutes. Residue current and power should disappear after that time, and it should be enough to clear all the errors.
- Use water with baking soda to clean the battery, and rinse afterward.
- Restore the battery. Reconnect the terminals.
- Start your car.
Now, after you’ve started the car, check if the problem is solved. Your car should start without any trouble, and the check engine light shouldn’t be on anymore.
Whichever method you decide to try, make sure you give your car a bit of time to re-learn. After every reset, it “forgets” what it knew before, so take it easy on the first ride.
Find a Professional
If you’ve tried one of these two methods, and the original issue remains, you need to take your car to a professional. Paying attention to the signals your car sends you is crucial. It keeps you and everyone else in the traffic safe.
Difficulties starting your car, check engine light going on, and burning smell can point out to a slight glitch in the system, but they can also indicate more serious issues. Therefore, you should never ignore them.
Final Thoughts
In summary, if you’re having trouble with your car, you may need to reset the car computer. There are two ways to do so – with battery on and with battery off. Make sure you allow some time for your car to relearn and take it easy on your first ride after the reset. Finally, if the problem is not solved, have a professional take a look at it so you and everyone around stays safe.
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