P0172/P0175 - cold weather
 

On my way home, the codes popped up.
P0172/P0175 It was a 10 mile drive in cold temps, 30F. It was colder this morning, 25F. The last time these codes popped up, it was a year ago in cold weather too. I reset them last time, they didn't come back until today. It took almost all 10 miles to get to the temp middle point. No traffic due to weather, so highway speed and 40+ MPH on side roads. The drive this morning was slow due to snow and ice patches.
Are these codes common in cold weather? The intake filter is about a year old. Time for a new one. Mahle filters are used for intake and cabin. :dunno:

Codes are reset so I'll see if the SES light comes on again. It passed emission testing last month, so registration is no problem this month.

Drove to the airport yesterday, it was 5F/–15C. No problem other than a weird screech from the starter. Heat came on quickly. No stumbles, smoke, etc.

I'd be screeching too if I was the starter...

Anyway I was getting those codes too, only it was last summer, so I don't think it's temperature-related. I disconnected the battery for an hour to reset "adaptations" I think it's called, and that fixed the problem if one indeed existed... no more codes. OK no more of THOSE codes.

Thanks for the feedback. I did check O2 readings. Front sensors were oscillating. Rear O2 sensors were steady. Closed fuel loop. It was @147F. It had cooled off a bit before I scanned it. Fuel trims were probably right under 0 once short term and long term are subtracted from each other. No light came on after driving to work this morning. I'll check fuel trims since everything was cleared out.

P0172 /P0175 - Those are codes for Rich fuel trims, right ? I might suggest you get a BMW-specific code reader...the P codes are too generic..

These cars have no consistent problem in cold weather - other than frozen door latches that won't latch. I started mine and drove it to the airport at -1 degree F...and that's not even that cold...

If it continues, you should measure actual long term fuel trims with INPA or OBDFusion or other app/scanner. You might also measure your fuel pressure at rail.

We've seen bad MAF's, faulty fuel regulator in new fuel filter (Hecht) leaking injectors and other things cause a rich condition.

+1
Getting a BMW specific scanner is a must!

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I have a Foxwell Pro 520. It was easier to grab an Actron scanner for codes. If they come back, I'll use the Foxwell. Since I've saw them over a year ago, the Actron was a quick choice. Air filter restriction can cause rich codes. I'll check the filter once it warms up this week.

Found two codes: E3/E4
AI search: The E3 and E4 Codes are adaptation codes. Any thing that that affects fuel/air mixture can set this code. The most likely source though is increased air not being measured by the maf.

Before scanning and search for codes, I look it over. I removed the air intake assembly for valve cover work. The air tube connection right after the MAF was not on good. The clamp was really loose. I fixed the connection and tighten the clamp. The BMW codes seem to line up with an air intake hose issue. I cleared the codes. I’ll post back after a few hundred miles of driving.

Thanks to Effduration for putting you on the right track ;)

Forgot to mention a clip was loose too. After resetting the codes, they have not come back. All emission tests have passed.

which MAF sensor are you currently using?
 

X5chemist- are you still using the cheap $20 MAF that you recommended to me over 2 years ago, and said that you had been using yours for a year at that time?

As you might remember, my problem was the opposite of yours, as I was getting lean codes P0171 & P0174 (I'm still getting comparatively high fuel trims) versus the rich codes you were recently getting. I'm not getting codes at this time, though it's probably because I routinely reset everything frequently, and often check for loose fittings, good O2 readings, and have smoke-tested maybe a dozen times. The cause of the high fuel trims remains elusive, after 3.5 years of searching for it. Congrats on solving your rich condition problem.

I'm about to give up using my $20 MAF (I have two of them), and try a mid-range cost, German-built MAF (Hella or Bremi), to try to get better fuel trim readings. The original? Siemens-VDO MAF I had was proven to be getting worse every time I cleaned and re-installed it, so though everyone seems to say that it is the only brand to use, I can't see my way to spend more $$ to get another one, only to see similar bad readings (mine got so bad, I took it apart to check for internal faults, but found none).