My brothers dodge had the same thing happen to it, but we fixed it quit easily because we didn't think it would have been that bad, it was running for a few months with the light on, so we just unplugged it, worked great.

 

usually you get po171 & po174 when it the pcv elbow. Bank 1 only I might think you might have an exhaust leak on that side. Could be your intake is leaking on that side..