How To Clear Engine Codes Without A Scanner (2023)

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This article will teach you how to clear engine codes without a scanner and will help you deal with problems that come with it.

But why should you pay attention to Engine Codes?

Years ago, cars just stopped, and you had no idea what was wrong with them. Those days are now gone. Today, your car warns you— it gives you some heads up when it has a problem. And it would be best if you listened when your car offers you these heads up. That way, you’ll be able to solve problems before they become big enough to disrupt your day.

Therefore, It’s essential to pay attention to these codes. They alert us to engine problems before they become big enough to stop the car’s proper running.


  • 1 How To Clear Engine Codes Without A Scanner
  • 2 What Problem Do You Experience After Clearing Engine Codes?
  • 3 What Should You Do If The Engine Codes Turn Back On?
  • 4 People Also Ask
    • 4.1 Why Is My Check Engine Light On But No Codes?
    • 4.2 Will Engine Codes Clear Themselves?
    • 4.3 Will Disconnecting Battery Clear Codes?
    • 4.4 How Can I Get Trouble Codes Without A Scanner?
  • 5 Conclusion

How To Clear Engine Codes Without A Scanner

How To Clear Engine Codes Without A Scanner (1)

It’s relatively easy to clear engine codes without a scanner. You can do it in as little as thirty minutes. Importantly, you won’t need anything but a wretch to get it done.

So if you want to clear these codes, roll up your sleeves and let’s get to work.

  1. The first step is to park your car on a level area and pop the hood. Before you pop the hood, make sure you’ve engaged the parking brake.
  2. The next thing is to remove the negative (-) cable from the battery. If the line is latched on too tightly, you may have to use a wrench to pry it open.
  3. When you’ve done, do the same for the (+) cable. After you’ve done removing both cables, ensure they stay far away from each other. Again, it would help if you made sure the (+) and (-) never come in contact.
  4. After you’ve done with the cables, cycle the ignition switch off and on about 3-5 times.
  5. The next step is to drain all the power in the ECU capacitor. To do this, press the horn on the steering wheel. Let it blow for at least forty-five seconds before letting go. By doing this, you’re removing all the electrical power that’s left in the ECU. You may be wondering why the horn can work, despite the battery being disconnected. The horn works because it is connected to the hot circuit. That’s why it can be engaged at any time.
  6. After this, reconnect the battery. While you can do this immediately, I’d advise you to wait for up to fifteen minutes.
  7. When reconnecting the battery, make sure that you reconnect the positive terminal first and then connect the negative terminal. Through all this, remember not to let the cables touch one another. When you’ve done, make sure that the cables are clamped tightly on the battery. Use a wrench to tighten their hold to be extra sure.
  8. Next, turn the ignition on and check for any warning lights on the console. If you followed all the steps to the letter, the engine codes would have disappeared.

What Problem Do You Experience After Clearing Engine Codes?

It’s relatively simple to clear your car’s engine codes. However, you may experience a few problems after removing them. Most of these problems are caused by the draining of the ECU of all power.

After the restoration of power, your car’s electronic gadgets may reset. It means that things like your clock, radio, and others will need to reboot.

Most times, this won’t amount to too much. Your car needs to reset. Driving it once or twice should be enough to restore its traditional settings. However, don’t be surprised if your car doesn’t act right for the first few drives.

You may also experience problems with the transmission. Since your car is rebooting its electrical systems, the transmission will act fuzzy for a while. You’ll need to drive for a while for it to reboot completely.

However, some cars won’t give you this problem. These cars use a memory device that stores all your electric settings separately. It means that you’ll always have a backup.

What Should You Do If The Engine Codes Turn Back On?

If there are still codes after following all the steps, you most likely didn’t drain the ECU completely. The solution to this is to repeat the entire process and remember to drain the ECU fully. That means you should hold down the horn until the ECU is all drained out.

You should also remember that just unplugging your car batteries won’t clear engine codes. It may work on older models, but it certainly wouldn’t work on newer cars. Any car made from 1996 downwards will have to go the full nine yards.

If the codes appear a day after you’ve cleared them, that’s a sign that your car has serious problems. You should get your vehicle checked by a professional if this happens to you. It’s a sign of issues that you cannot solve on your own.

People Also Ask

Why Is My Check Engine Light On But No Codes?

If this has happened to you, there’s only one answer. You’re using the wrong scan tool. That’s it. No more, no less. Whenever there’s an engine light, there’s always a code stored. The problem is getting the right scan tool to get the code. If you’re facing this problem, change your scan tool.

Will Engine Codes Clear Themselves?

Cars don’t cure themselves. If there’s an engine code, it won’t clear by itself. However, if you inadvertently fix the problem ( like putting the gas cap back on after refueling), it may clear. Asides from that, the engine will not fix itself. So, no, engine codes don’t clear themselves.

Will Disconnecting Battery Clear Codes?

If your car was manufactured before 1996, you only need to disconnect the battery to clear the codes. However, the best way to clear codes is to use a scanner. If you don’t have a scanner, and your car was made about 1996, you’ll have to follow the steps above.

How Can I Get Trouble Codes Without A Scanner?

All you need to do is flip the ignition switch a few times without cranking the engine. Make sure you finish with the key in the on position.

Afterward, your car will search for any saved trouble codes. When this is done, the service engine light will light up. When this happens, start paying rapt attention.

The light will start to blink. Each pulse of light represents a number, and a pause means a break to the next number. Quick flashing represents 0. For example, “20” would be represented by pulse, pulse, pause, rapid flashing. When you get the code, check your repair manual for what they may mean.


There’s an easy and short way to clear engine codes without a scanner. All you need to do is disconnect the battery and drain the ECU of power. If you do that, all engine codes will be cleared immediately.

However, if the codes reappear after a day or two, you should have your engine checked out. There may indeed be a problem with it.

Read more: OBD2 Freeze Frame Data: How to Interpret And Use It?


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