How To Clear OBD2 Codes Without A Scanner

It’s easy to clear OBD2 codes without a scanner in just a few simple steps. The process can be done in just a few minutes, and it won’t require any equipment, except for maybe a simple wrench.

How To Clear OBD2 Codes Without A Scanner

But what exactly are OBD2 codes, and why should you pay attention to them? OBD2 codes cause your check engine light to go on. This could indicate a wide range of problems, from minor issues with your gas cap to significant problems with your transmission.

Although you can clear an OBD2 code without a scanner, turning the check engine light off is not always the right solution. If there is a serious problem that needs fixing, the light will come back on soon after you turn it off.

Here’s how you can easily clear your car’s OBD2 codes. If you notice that the light comes back on soon after, then you should have your engine checked out to make sure that there isn’t a serious issue.

Resetting OBD2 Codes

Resetting OBD2 codes without a scanner takes just a few simple steps. Here’s what you’ll need to do:

  • Make sure your car is parked in a level area, then pop open the hood
  • Remove the (-) cable from the terminal. You may need to use a wrench if it’s latched on tightly
  • Perform the same procedure, but with the (+) cable. Always make sure that the two cables stay well away from each other
  • Once you’ve removed the cables to the battery, you’ll need to cycle your ignition on and off. This should be done anywhere from 2 to 5 times
  • You’ll need to drain out any extra power that’s still left in the ECU. To do this, hold down on the horn of the steering wheel. The horn will use up any power that’s still in the circuit so that the ECU is fully drained. This can take anywhere from 30 seconds to a minute, so keep laying on the horn
  • Although you don’t have to, it’s best to wait a minute or so to reconnect the battery
  • Clamp both of the cables back on the battery, starting with the red and then moving to the black. As always, check to see if the clamps are tightly latched to the terminals
  • Turn the engine on and check for any lights on the console. By the time your engine warms up, any warning lights should be off

If you still notice a check engine light once you turn the engine on, you likely didn’t fully drain the ECU. Repeat the procedure, making sure to press the horn until the ECU is drained of all power.

Remember, simply unplugging your battery won’t be enough to clear OBD2 codes. This works on older cars that just use OBD1 codes, but most cars made after around 1996 will require the full process described above.

If the light comes back on within a day of clearing OBD2 codes, this is a sign that you need to get your car checked out for more serious problems.

Problems After Resetting OBD2 Codes

Although resetting OBD2 codes without a scanner is a fairly simple process, you might still notice a few small issues once your car restarts.

That’s because you have to drain all of the power from the ECU to reset the codes. When power is restored, many of the electronic settings in your car will need to reboot. This can also mean that your clock, radio, and drive settings could be reset.

In most cases, these issues aren’t much to worry about. Your car needs to reset to all of the right settings after the ECU is drained. This can take at least one drive cycle, so don’t worry if your car isn’t acting right from the moment you turn it on.

Them most common problem you’ll have is with the transmission. Since your car is rebooting all of its electronics, the shifting in its automatic transmission won’t reset perfectly right away. You’ll have to drive for a bit before it returns to normal.

Some cars also have built in modes that preserve your settings even if the ECU is drained of power. They use a memory device that stores these settings separately, so you always have a backup.

What To Do If OBD2 Code Comes Back On

If reset OBD2 codes without a scanner and notice that the check engine light comes back on quickly, this is a sign that there’s a serious problem you need to get checked out.

Keep in mind that check engine lights aren’t just there to annoy you. If the light keeps coming back on, take it seriously and go get your car checked out.

The best way to do this easily is with an OBD2 scanner. They are widely available, and they won’t cost you much. They can help you find out what’s going on with your car so that you can get it checked out.


If you notice a check engine light, you might be tempted to reset your OBD2 codes right away. Although these warning lights are annoying, they are there for a reason.

Before you clear out your OBD2 codes, you should do a quick check of your engine to make sure that everything is functioning as it should. You can also use an OBD2 scanner to see what the issue is if you have one lying around.

If you just want the warning light to go away, then follow the steps described above to quickly clear OBD2 codes and get the light turned off. The process takes just a few minutes, and it’s easy to do on your own.

Once you’ve cleared the codes, see if the light comes back on within the next few days. If it does, don’t just clear out the codes again. You likely have an engine or transmission problem that needs to get checked out. Perform a quick systems check, or have a mechanic handle it for you.

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