P0171, P0174 resolved

[flatlander]

Originally Posted by boywondergq1

So for those following my story, I should note that right after I replaced those two hoses and started it up the first time a puff of black smoke came out of the exhausts. I wonder what got in there after replacing the hoses to cause that, or if that incident messed up the O2 sensors.

My 'CAT not ready' finally went to 'ready'. So far so good. A few days later, 'EVAP not ready' finally came ready as well after about a tank of gas worth of driving for 2 weeks. Shortly thereafter, some new codes appeared:

P1158 and P1160: Fuel Trim Adaptation Additive Low (Bank 1) and (Bank 2) <-- (from what I've googled)

Does this mean the 2 oil separator hoses I replaced did something? I've read that the Fuel Trim Adaptation 'adusts itself' over time. Do I need more time? Do I clear these and wait again?

Hmm. Mass Air Flow sensor? Yeah, called BMW and they want $695 CAD for a new one. I haven't had much luck with cleaning these.

I think I'm ready to throw in the towel on this one.

I've replaced the oil sep hoses too. I was still getting P0171 and P0174 codes that would not stay reset. I cleaned the MAF, but that did not change the outcome.

Then I ordered a new MAF online. The new MAF worked fine, giving a smooth idle. When I checked the active codes, the P0171 and P0174 were inactive. I cleared them to reset the CEL and it's been all clear for 4 days.

Try cleaning the MAF and if that doesn't work, you could try to swap MAF's with someone who has the same engine to troubleshoot, or just bite the bullet and order a new one.