[UncleRashid]

Hey all,

i purchased a 2014 550i xDrive and i’m absolutely in love with it. The only issue i have had that has been driving me bonkers is that, after a month of ownership, i get a CEL for P0136 Heated oxygen sensor 2, bank 1 - circuit malfunction. Before i bought the car from the dealer it had the same issue (it came up during test drive), and the sensor was replaced before i bought it. When it came back I took it to the same European speciality shop it was originally serviced and we did a process of elimination. Updated the software and the code came back, replaced the sensor again and the code came back. Note, when the code is cleared it could sometimes take a day or two for the code to reappear.

Now, the shop says that the culprit could be cracks in the air ducts parts 13 71 557 451, 13 71 557 452 causing a slight vacuum leak. the owners of the shop showed me how it’s loose, and that if it’s replaced it should fix the problem.

Has anyone had experience with this issue? is the air duct causing this problem? I knew N63s and the TUs could be a PITA but I wasn’t expecting something like this!

Many thanks

[Aussie_550i]

I had similar issues and after much searching and reading, found the the MAF sensors can also trigger this error. I replaced both and error went away.

Hope this helps you.

[UncleRashid]

i think i’m going to consider doing that now, along with some other tests, after this post I got another code for a different sensor, P0141. Dealership says if the codes come back then it’s possible that it could be an electrical issue, almost $6000 repair!!! crazy part is I got a CEL again yesterday, this time for both P0141 and P0136

[Bitchn5ive]

What ended up being the issue?

[UncleRashid]

I haven't yet found the issue, a BMW dealer told me with confidence that the O2 sensor wiring harness would have to be replaced if it comes back. I also had the DME reprogrammed according to the SI B12 16 15 service bulletin for the 12B801 codes. Now this CEL is still back but intermittent, and the following codes come up (I've been using BimmerLink to scan instead of using the generic codes):

12AB04 - Lambda probe after catalytic converter, electrical: open circuit
213601 - Power management: Quiescent current violation (might be from my dashcam hooked up to my fuse box running 24/7)
12B701 - Lambda probe heating after catalytic converter, function: internal resistance too high

the light will go away and the codes are stored, and I have no clue what to think. The dealer never explained why or how the wiring harness could be the issue, and I don't necessarily mind having it done since I have an extended warranty, I just don't want this to end up being a waste of time.

edit: the air ducts were also replaced, so I suppose we could rule that out

[Hellboy550i]

Originally Posted by UncleRashid

I haven't yet found the issue, a BMW dealer told me with confidence that the O2 sensor wiring harness would have to be replaced if it comes back. I also had the DME reprogrammed according to the SI B12 16 15 service bulletin for the 12B801 codes. Now this CEL is still back but intermittent, and the following codes come up (I've been using BimmerLink to scan instead of using the generic codes):

12AB04 - Lambda probe after catalytic converter, electrical: open circuit
213601 - Power management: Quiescent current violation (might be from my dashcam hooked up to my fuse box running 24/7)
12B701 - Lambda probe heating after catalytic converter, function: internal resistance too high

the light will go away and the codes are stored, and I have no clue what to think. The dealer never explained why or how the wiring harness could be the issue, and I don't necessarily mind having it done since I have an extended warranty, I just don't want this to end up being a waste of time.

edit: the air ducts were also replaced, so I suppose we could rule that out

I had this sane issue even after the oxygen sensor is changed the 12b801 codes comes back the bmw dealer gave me 3000$ to change wire harness , I didn’t change it , after some time it’s gone .

[Wells535]

Has anyone found a solution ? I have the same problem and they are indicating an engine harness $10k

[UncleRashid]

After months of driving with the CEL coming and going, I have found my issue. Granted, I feel the issue could be different for others.

I took the car to an indy shop that has worked on it since I bought the car and after they inspected the wiring harness they found one section of it leading to the DME was corroded. He did replace only that section that was corroded and soldered everything together, so far so good. We will see how everything holds up in the future. As for all the O2 sensors, they were still in fantastic condition, so at least we had that.

Will update if anything occurs.

Originally Posted by Wells535

Has anyone found a solution ? I have the same problem and they are indicating an engine harness $10k

I would recommend you take it somewhere other than the dealer, they gave me the same quote to replace the harness, if you can find a reputable independent euro/german shop they should know what to do. Best of luck!