My check engine light came on today, the car is running smoothly, oil was recently changed as well as power steering fluid being filled. As I was checking fluid levels and looking under the hood for anything out of the ordinary, I noticed on the drivers side, high up sort mirrored to where the cabin filter is on the passenger side, there is a fairly thick hose that is only connected to anything on one side, I looked for any possible connection underneath and didn't find anything. Any suggestion to what this part may be? I will post pictures of the location and of the hose when it is daylight. Thank you for any help!