Hello and welcome to JustAnswer!
Is it the check engine light that's coming on, an orange outline of an engine? There are several things that will turn the engine light on.
When the light is on that is because the powertrain control module (PCM) has seen a problem somewhere in a monitored system and set a fault code. THe problem could be transmission related, evaporative emissions related, any of the sensors on the engine or transmission, the catalytic converter, loose or bad fuel cap, etc. There are dozens of possible fault codes that can set.
The first step in diagnosing the problem is seeing what fault codes are stored. This can be done with a scan tool or code reader or with the built in feature by cycling the key three times.
If you know what fault codes are setting then let me know and I'll be able to give you possible causes based on the codes.
If you don't know what codes are stored then we can try the built in code read feature and see what comes up.
If the orange outline of an engine isn't the warning light you are seeing then please describe the color and shape of the light.