The check engine light usually comes on when there is a problem with the gas emission control system or other system controlled by the on-board computer. Turning it on generates a code that can help you define the problem in order to fix it. You may need to manually reset the light after the repair, if the code does not clear automatically. The best way to reset the engine light is to use a code scanner. However, if your vehicle was manufactured before 1996, you will only need to disconnect the battery to reset it.
Steps
Method 1 of 2: Use a code scanner
Step 1. Use an OBD-II scanner
“OBD” stands for “On-Board Diagnostics” and OBD-II scanners are compatible with all vehicles made after 1996. Buying a code scanner can be expensive, so it's best to borrow one., unless you use it frequently. Some garages can lend a scanner to their very good customers, but you can also borrow one from a friend or family member.
Note that some vehicles manufactured before 1990 may not have an OBD port under the dashboard. But if there is one, it might be an OBD-I port instead of an OBD-II port, so you will need a different scanner
Step 2. Plug in the scanner
Modern vehicles have a specific port for the OBD scanner. You will find it under the steering column. Once you locate it, connect the scanner cable to it. If you cannot find the location of the ODB port, refer to your vehicle manufacturer's manual.
Step 3. Turn on the device
Switch on the ignition of your car first, without starting the engine. When the dashboard lights up, turn off all electrical accessories in your car, such as the radio or the dash cam. After that, press the button Read (read) the scanner to check the engine light code.
- The code is a series of letters and numbers. Write down any codes that appear, so you can check what they represent and make any necessary repairs.
- Some scanners will explain the codes, while others will not. If you don't see an explanation attached to the code, look it up in your car's owner's manual or on the internet.
Step 4. Clear the codes
After reading the codes, press the button Erase / Clear (Wipe off). By clearing the codes, you will temporarily turn off the check engine light. After pressing Erase / Clear (Clear), wait a bit until you see it displayed No codes (No code), you can then switch off the ignition of your car. However, clearing the codes will not solve the problem. If your car's engine light comes on, it's best to take it to a garage for a professional diagnosis and have any repairs done.
Warnings:
when the OBD system is reset (which will happen after a certain number of kilometers, depending on the vehicle), the light will come back on, if the problem has not been fixed.
Method 2 of 2: Disconnect the battery
Step 1. Open your hood
Once you have located the battery location, remove the negative cable using a wrench (socket or adjustable). The negative cable is usually covered by a cap with a minus sign engraved on it.
Warnings:
Deleting codes by disconnecting the battery can also erase the memory of your radio and other accessories.
Step 2. Drain the capacitors
Press the horn for 30 seconds or turn on your headlights to drain the residual electricity. Neither the horn nor the headlights will work because the power is not plugged in, but by doing this you will be draining the remaining electricity in the capacitors.
Step 3. Wait 15 minutes
Leaving the battery unplugged for 15 minutes will allow your vehicle's system to reset when you plug it back in. Reconnect the negative cable to the terminal and replace the cap (if present). Since you have disconnected the battery, the error codes are cleared and the engine light has gone out.
Advice
- Seek advice from a mechanic if you need help turning off the engine light or figuring out the meaning of an error code.
- Serious mechanics will not reset the engine warning light without at the same time intervening on the problem that caused it to come on.
Warnings
- Use caution when disconnecting and reconnecting the battery.
- Your vehicle's emission controller will also be reset. This means that you will not pass the emission test, if you bring your vehicle in for a check, right after you have cleared the codes. Drive for at least 300 km before bringing your vehicle to the technical control.