Some Auto Parts store now have the tools to read codes
How do you reset check engine light for the 2009 Chevy trail blazer?
Check for vacuum leaks.
Check the motor mounts.
Random cylinder misfire
Check the engine thermostat. Its probably stuck open.
Bulb may be blown or has been removed.
Check
i would check to see if the o2 sensors have gone bad they will throw you a check engine light when they go out I have the same problem. It is the transmission. I have a 1999 Chevy Blazer and shortly after the Service Engine Soon light came on, my transmission started "slipping" between 1st and 2nd on an automatic. This only happens when the car gets warm on trips longer then about 15 miles.
check your owner's manual Check for vacuum leaks (replace all vacuum hoses anyway, they are cheap) but also remove and clean the EGR valve.
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.
The check engine light is triggered by the Engine Control Module (ECM). The ECM receives information from many sensors and determines when to illuminate the check engine light.
Check for vacuum leak