When the check engine light is on, the computer sets a fault code. Most auto parts stores will check this code for free and tell you how to fix it.
The "Check Engine" light means that the computer has stored a fault code. You need to use a code scanner to read the fault code. Code scanners can be borrowed, rented or purchased at most auto parts retail stores.
you have a fault code on emission systems
The check engine light indicates the computer has found a fault and stored a fault code. Many auto parts stores will pull the code for free and tell you what may be causing the issue.
You need a scan tool to read fault codes.
If the check engine light is still on there is still a problem. When you fix the problem the light will go out by its self and the fault code will stay in the ecm as a stored code until it's reset.
If you are referring to the Check Engine light it is on because the computer has set a fault code due to a problem with the emissions system.
Code P0731 means A/T first gear signal fault
WHENEVER the check engine light comes on, ALWAYS connect a code scanner to figure out why. The light is on to tell you that the computer has detected a "fault" and it wants to tell you all about it.
The check engine light is an indicator that the computer has detected a fault in one or more of the electronic components. Use a code scanner to figure out what is wrong.
You clear the light with an OBD2 scan tool after the problem that set the light and fault code has been repaired.
The check engine light indicates that the computer has detected a "fault". Use a code scanner to find out what the computer has detected, that is PROBABLY the reason the engine is running poorly.