Safest Way To Reset A Car Computer (Step-By-Step)

You should not wait to reset a car computer if there are some issues. Resetting the ECM (Engine Control Module) is not so hard, and you don’t need to be car tech-savvy. And resetting a car computer is completely safe.

By following some proper ways can be enough to reset a car’s computer memory. It will just take a little bit of time and minor knowledge about your car sensor (also known as car computer).

Surprisingly, most car owners don’t give sufficient attention and willpower to do it by themselves. But, if you learn the process of resetting a car computer which will save you money and time for a lifetime. So, Let’s know how it’s done.

What Is ECM In Car | Car Computer

Nowadays, car manufacturers produce at least one computer in every car. A car computer has lots of names. Some of them are Engine control module (ECM), Engine control unit (ECU), Car sensor, etc.

The car computer or an ECM is an electronic control unit that operates a series of actuators on an internal combustion engine to ensure good engine performance. The car computer receives various types of information from different different sensors in your car.

What Does A Car Computer Do

The car computer’s job is to get information from some sensor in your car sensor like the air pressure, the engine temperature, oxygen, and the knock sensor. After collecting all of the information from these sensors, the car computer controls the spark plugs, fuel injector, and other components to regulate and work efficiently.

Fortunately, When your car computer has some issues with operating properly in your car, it shows warning signs. So, you can fix these issues in your car right away and let the car computer work efficiently. For example, if you see check engine lights keep coming on, that means something is wrong with your car computer.

How To Reset A Car Computer

How to reset a car computer

In order to reset a car computer, you can follow two ways to do it. One is you can reset your car computer with the battery off. And another way is you can reset your car computer without disconnecting the battery.

Fixing any car computer issues is simple because cleaning or resetting codes from the car computer can help you fix that issue in your car. Manually resetting the car computer is still a popular and effective way.

What you will need to reset a car computer:

  • Only a pair of pliers or fuse puller (a pair of pliers would be better)

Here is the step by step process of how you can reset your car computer with the battery off:

Step 1: Open up the hood

To reset a car computer, you have to open up the car hood.

Step 2: Remove the positive terminal cable from the battery

After opening up your car hood, you will see your car battery. Now you just need to remove the positive terminal cable from the battery using pliers. Make sure you remove the positive terminal cable completely.

Step 3: Find the car’s fuse box and remove the fuse

Remove the fuse

Locate your car’s fuse box and remove the cover. But, before removing the fuse, look at the diagram. Remove the fuse that has “ECM” labeled on it.

Step 4: Leave the fuse for a little

When you remove the fuse now, you just need to leave the fuse a few times before reinstalling it because it will help to clear the computer’s memory completely.

Step 5: Reinstall the fuse and reconnect the battery terminal

After a few moments now, reinstall the fuse and reconnect the positive battery terminal. Ensure the battery positive terminal is reconnected again.

Step 6: Start the vehicle and go for a test ride

You have completed resetting the car computer properly if you follow these steps correctly. Now, you can start your vehicle and go for a test ride to help the car computer to monitor all the sensors and register the results again. You also should see the check engine light is off.

You just knew how to reset a car computer safely. If you follow these steps properly, you should be able to reset the car sensors. As a car mechanic, I always recommend you to reset your car computer with the battery off. Resetting a car battery, it’s just reinstalling the ECM fuse. There is also another way to reset a car computer that is reset without disconnecting the battery.

How To Reset Car Computer Without Disconnecting Battery

You can also reset a car’s computer without disconnecting the battery. If you follow these methods to reset a car computer, you won’t need to disconnect the battery. Both methods are almost the same when resetting a car computer with a car battery on and off.

What you’ll need to reset a car computer without disconnecting battery:

  • A code reader.
  • A pair of pliers

Whether you reset your car computer with battery off or battery on, a pair of pliers always be needed. That’s why you should get a pair of pliers.

Here is the whole process of how you can reset a car computer without disconnecting battery:

Step 1: Open the hood and find the car’s fuse box

When you open the hood of your vehicle, you will see there is a fuse box. Fuse box located just behind the car engine.

Step 2: Remove the Fuse cover

After locating your car fuse box, now you just need to remove the fuse box’s cover smoothly. Don’t hurry to remove the fuse cover.

Step 3: Remove fuses

When you find the fuse box and uncover the box, now you need to remove them. But, make sure you remove fuses that have “Back-up” and another one “EMU or ECM” labeled on them. These two fuses you will need to remove or pull out from the fuse box.

Step 4: Leave the fuses and reinstall

Leave those two fuses for a few moments; around 10 minutes to 15 minutes would be appropriate. Don’t leave fuses for a long time out of the box or not so little of time. After 10-15 minutes, reinstall fuses properly.

Step 5: Put the fuse cover back

You shouldn’t forget to put the fuse cover back because, without cover, fuses are very vulnerable. Without a fuse cover, the fuse can be broken anytime. So ensure you put the fuse cover back.

Step 6: Go for a test drive

Drive your car

If you followed all of the steps, then you reset your car computer with battery. So, it’s time to see whether you reset your car computer or not properly. First, go for a test drive with your car, which will help your car computer set up and monitor your car. You should notice the car’s performance on the road and check the engine light when you drive the car. Check Engine Light should be off after you reset your car computer.

How Do You Know If Your Car Computer Or ECU Is Reset?

There are some simple ways to know if your car computer or ECU is reset successfully. One of the easiest ways to tell if a car computer is reset is by checking the Check Engine Light (CEL). If CEL is off, that means you have successfully reset your car computer.

Here are some ways to know if the car computer is reset:

  • After you reset a car computer, you will change the car’s performance. The car performance would be so smooth, and there would be no glitches on the road.
  • Check Engine Light (CEL) will be off completely. This is the most common way to know if your car computer or Engine Control Unit (ECU) is reset.
  • The car’s Trip meter (also known as trip odometer) will be read at 0. If you read 0 on the trip meter, that means you successfully reset your engine control module.
  • Another simple way to tell if a car computer is reset is that your radio stations will need to be reprogrammed.

These are the ways to know if your car computer is reset. First, you should confirm that the car computer is reset completely and properly. With those indications in your car, you can tell you reset your car correctly.

How To Disconnect A Car Battery To Reset The Computer

There is not really a big difference between typically disconnecting a car battery and disconnecting a car battery to reset the computer. Whether you reset your car computer or battery replacement, you need to know how to disconnect a car battery.

Let’s see how to disconnect a car battery to reset a computer:

  1. Locate the battery under the hood.
  2. Choose the right socket.
  3. Disconnect the negative battery terminal. (whenever you disconnect the negative battery terminal, you should be careful)
  4. Disconnect the positive battery terminal.
  5. Now, your car battery is disconnected, and your car is ready to reset a computer.

To reset your car damage computer, you will disconnect the battery. That’s why you can follow these simple steps to disconnecting your car battery.

Frequently Asked Questions (FAQ)

How much does it cost to reset a car computer?

Car computer reset costs depend on the car’s model. An average car computer or Engine Control Module (ECM) reset or reprogram will cost you between $120 to $250. And when you reset your car by a mechanic, then the labor cost will be added. To car computer resetting labor costs will also cost you around hundreds of dollars more.

How long does it take for a car computer to reset?

A car takes around 30 minutes for the computer or ECU to reset because the car computer needs to reprogram computer codes which will run your car smoothly. Therefore, you should give this amount of time to the car computer to be reset properly.

How long to disconnect battery to reset car computer?

You should disconnect the battery for 15 minutes to reset the car computer because this amount of time will help your car computer or ECU to forget the previous code. That’s why you should leave your car battery for some time to reset the car computer properly.

How many miles to reset computer on car?

You need to drive about 50 to 100 miles after resetting a car computer. You may know that after resetting your car computer, you will need to drive your car, which helps the car computer to monitor all the sensors in your car.

Can a car run without ECU?

The Engine Control Unit (ECU) or car computer is the brain of a car’s fuel injection system. And a fuel injector is a necessary component of your car. So, without ECU, a car can’t run. But, a car can run with a bad or damaged ECU.

Final Thought

Now you have known ways of resetting a car computer. Car reset processes are the same whether you drive a smart car (Electrical car) or patrol car. That’s why you should not worry if you are driving an electric car. Resetting a car computer is just cleaning the codes in your car computer’s program.

Another thing you should be certain of when you want to reset your car computer is to make sure your car computer shows a warning sign in your car. If you can’t be certain that your car computer needs to be reset, you shouldn’t reset the car computer. Instead, talk to your mechanic or go to an auto shop to be certain and clear about your car’s computer warning sign.

But if you are certain that your car computer or ECU needs to be reset, don’t wait for the right time; you should immediately reset your car computer memory. A faulty car computer can cause tiny issues for your car performance, but if a defective car’s ECU stays for a long time, it can cause massive issues in your car. That’s why you should be more careful about your car’s computer warning signs.

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