The check engine light is on, but there doesnn't seem to be a problem otherwise.

If your gas cap is not on tightly this will cause check engine light to come on. I found this out from my mechanic. This happened after I went to a full service gas station and I remember not hearing that distinctive crank sound when he put my cap back on but didn't think nothing of it until an unusually cold snap in weather happened that evening (which can also trigger this light) made it go on so I turned my gas cap tighter and the light went off.