The check engine light (service engine soon) comes on and stays on when a problem is detected by the self diagnosis system of your vehicle. Generally, the problem is in the emissions or something that is affecting the effectiveness of the emissions, but other causes can trigger the light to come on, too. To determine the cause, the vehicle will need to be taken to a parts store or a shop that has an OBD2 scanner, or for 1995 and earlier models, an OBD1 scanner, While a scanner will not give you the magic answer, it will give you a code that narrows down the problem area.
If the check engine light is illuminated, start with scanning for codes.
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.
Check your fluid levels.
check power to fans,if power check fan sensor!!
Fix the problem causing them to be on.
There is an engine misfire, probably spark plugs issue.
There should be a dipstick like the one for oil. Check with engine running.
The most likely cause o f the check engine light is that the belt was not tightened properly. It may also be that the belt stretched and needs to be retightened.
Get the computer scanned to see what the problem is.
(torque converter clutch circuit performance or stuck on)
Check your coil pack or the spark plugs.
Disconnect the negative battery terminal for at least 30 seconds.