How to Reset a Check Engine Light

A cheap, ODB 2 scanner in red.
  • 1 hours
  • Beginner
  • 0-50
What You'll Need
Car manual
Automotive scanner
What You'll Need
Car manual
Automotive scanner

Have you repaired a car problem that illuminated the check engine light, only to realize the light hasn’t shut off? Resetting a check engine light can be a complicated process for a lot of modern car owners.

A few years ago if this light came on, disconnecting and reconnecting the battery would solve the problem. Today, most modern cars are installed with the OBD 2 system (On-board Diagnostic System).

You may still attempt to reset the light by simply disconnecting the battery, but having the right precautions in mind will help you a lot in deciding whether or not you should do this.

Determine Whether Your Car Has OBD 2

Most cars manufactured after 1996 were fit with OBD 2. Simply disconnecting the battery to induce a reset is not guaranteed to work. Try to browse through your car manual to gather as much relevant information as you can to know why disconnecting the battery will not work.

Consequences of Disconnecting the Battery

The OBD 2 system requires a constant flow of energy to keep the car memory accessible. If your vehicle is equipped with an anti-theft system, it is possible that your car will stop functioning completely once you disconnect the battery, causing further complications.

If you think you can disconnect the anti-theft system with some help, then you could go through with this.

The radio memory can be lost too and you will have to enter a code to access it again. The code can be a pain to find, too, especially if you purchased your car secondhand.

The original car manual can have the security code, so try to get hold of that before doing anything if you're considering disconnecting the battery.

Disconnecting the car battery can also cause stored onboard memory to be lost. Onboard memory usually saves your driving patterns and other important information like gear shifting. The car will have to take time to learn all these patterns again when you reconnect the power.

Buy an Automotive Scanner Instead

Although disconnecting and reconnecting the battery may help, the best and simplest way to reset your check engine light these days is to buy an automotive scanner. You can purchase one cheap at car stores or buy it easily online.

Connect the automotive scanner to the car and that’s it. The job is simple. The scanner will get rid of the check engine light, and as long as the problem has actually been repaired it should not come back on again until you have another problem.

You will not have to go through the complications that come with disconnecting and reconnecting the battery this way, and in the event that you don’t know what’s caused your light to come on in the first place, this device can give you a code to figure it out.