The corect and only real way:
Have the car scanned, this will tell you what is wrong.
Repair the fault.
Have the car scanned and re-set.
If you re-set the system without repair it will just come back on.
Here a answer maybe CHECK THE ENGINE:) the light will go off
why does my check engine light stay on and want go off
"Check Engine" light comes on when you turn ignition switch on and should go off when engine cranks.
The check engine light comes on in a car when there is a problem with the engine. It will go off or be reset when the problem is fixed.
A Check Engine light can be reset by fixing the problem that caused it to go off. The codes that caused the light to go off can be cleared with an OBD II scanner.
There are pages and pages of things that can cause a check engine light. You need to have it checked with a scantool. Then the code can be diagnosed and repaired.
To check a engine light you need some kind of scan tool and it will show you what kind of code or codes is set for the engine light to go off.
Turn on the ignition and look at the instruments. You will see the Check Engine Light come on for a few seconds and then go off. If you see the light it is working.
The Check Engine light is on because there is a problem with the emissions system. Once you have the problem repaired the light will go off.
Check engine lights will not turn off in a vehicle until they are reset. To reset the light on a 1994 Toyota Tercel pull the ECU fuse.
If the check engine/service engine light is on, the problem most likely isn't in the ECM. Get it fixed, and it should go off.
One way to reset a Kia Rondo check engine light is to disconnect the battery for up to one minute. After the battery is reconnected, the check engine light should be off. If the light does not go off, there is a problem with the car and it will need to be checked out.