OBD II Error Codes P1086, P1084, P0172, P0175

[AceWynn]

Hey Guys,

My Service Engine Soon light just came on. Took out my OBD II scanner and the following codes came up: P1086, P1084, P0172, P0175.

I looked up P1086 and P1084 on this forum and found out that Fuel Control Mixture Lean (Bank 1 Sensor 1) and Fuel Control Mixture Lean (Bank 2 Sensor 1). I have no idea what this means. Can anyone help me with this? Is it the 02 sensors? If so where are they located.

For these codes P0172 and P0175, I found this thread: http://www.xoutpost.com/bmw-sav-foru...0175-dtcs.html
What should I be looking for when trying to fix this problem?

Thanks guys!

[AceWynn]

So the SES light came off a couple days after. I did change out the the pre cat o2 sensors because I was advised they should be replaced every 100k miles and my x5 is about to hit 120k. I would change out the post cat ones but I am under the impression that they don't do much. I also changed out the "tube Elbow - Throttle Housing to Air Boot." I hope this helps other users with similar issues like mine.