Bearings and O2 Sensor on 1998 Dodge Stratus

I just purchased a 98 stratus with 106xxx miles on it. The check engine light comes on and it throws an oxygen sensor code. I was wondering how you replace it/where is it located?

Also the car seems to make a humming noise at 35+mph, noise stops when I turn corners or curves in the road. Could this be the bearings or just tire noise?

Asked by for the 1998 Dodge Stratus
There are two O2 Sensors, upstream and downstream. The diagnostic code will point the tech in the right direction as to which sensor may be defective. To determine the cause of the humming noise, first, rotate your tires as described in your Owners manual. the drive the vehicle. If the noise is gone or is present in a different location, your tires are the source. If the noise remains constant from the same area of the vehicle, the wheel bearings of that particular axle should be examined. Feathered or cupped tires are common to Front wheel Drive vehicles and scheduled rotation is important to tire life.