Home Forums Articles How To's FAQ Register
Go Back   Xoutpost.com > BMW SAV Forums > X5 (E53) Forum
Fluid Motor Union
User Name
Password
Member List Premier Membership Search Today's Posts Mark Forums Read

Xoutpost server transfer and maintenance is occurring....
Xoutpost is currently undergoing a planned server migration.... stay tuned for new developments.... sincerely, the management


Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 11-22-2022, 03:13 PM
Member
 
Join Date: Feb 2019
Location: Caroline County, MD
Posts: 239
lkv0315 is on a distinguished road
P0174 & P0171

Hello everyone,
I've done some searches around the forum and for BMW cars in general for what these two codes could mean, and there are a lot of things that can cause these codes, and I'd like to fix whatever is causing the issue without replacing every single component listed. So I figured I would explain the situations in which it comes up, to see if anyone has some insight on how to narrow down the actual cause.
The codes come up very infrequently, however it is always in the same kind of situations, if I commute longer distances, 75+ miles in one drive, it will come up at the end of the next drive normally. My most recent time encountering was over a 300-mile drive and it showed up after a 10-mile drive the next day. To clarify, the engine is the 3.0. I don't really see much of a performance change, however, I know running lean can make the engine run hot, and that's a situation no one wants. If any of this was helpful to the diagnosis, let me know what you think, or if you have any other questions that could indicate the issue, please feel free to ask.

P.S. I've already inspected the intake boot and intake system and haven't found any damage or leaks, except for the accordion that goes between the ram air scoop and the intake box, but it is a very small hole.
__________________
2005 X5 E53, 167k Miles: Kenwood DNX893S Head Unit, Mud Flaps (Rear Only) , Rim Shopping(WIP), Full Spectrum RGB Halos,
Reply With Quote

Sponsored Links

  #2  
Old 11-22-2022, 04:59 PM
Member
 
Join Date: Jan 2016
Location: Michigan
Posts: 370
ahlem is on a distinguished road
What scanner did you use to read the codes?
__________________
2001 x5 3.0, 1990 e30 M3, 1991 318is, 2002 325i, 2008 335i Dinan stage 3 6 speed,
Reply With Quote
  #3  
Old 11-22-2022, 06:16 PM
Member
 
Join Date: Feb 2019
Location: Caroline County, MD
Posts: 239
lkv0315 is on a distinguished road
I used a generic iPhone compatible Bluetooth OBD scanner, but this same code comes up when I use PAsoft so it should be correct.
__________________
2005 X5 E53, 167k Miles: Kenwood DNX893S Head Unit, Mud Flaps (Rear Only) , Rim Shopping(WIP), Full Spectrum RGB Halos,
Reply With Quote
  #4  
Old 11-22-2022, 07:42 PM
workingonit's Avatar
Member
 
Join Date: May 2021
Location: DFW Texas
Posts: 468
workingonit is on a distinguished road
P0171 & P0174 codes; a bane to many BMW owners

Quote:
Originally Posted by lkv0315 View Post
...
The codes come up very infrequently, however it is always in the same kind of situations, if I commute longer distances, 75+ miles in one drive, it will come up at the end of the next drive normally. My most recent time encountering was over a 300-mile drive and it showed up after a 10-mile drive the next day. To clarify, the engine is the 3.0. I don't really see much of a performance change...

P.S. I've already inspected the intake boot and intake system and haven't found any damage or leaks, except for the accordion that goes between the ram air scoop and the intake box, but it is a very small hole.
I fought the same codes for 7 months (along with random misfire/low fuel pressure codes) constantly checking for vacuum leaks (none found) or a fuel pressure loss (none found), in vain.https://xoutpost.com/bmw-sav-forums/...-codes-me.html Though the codes showed misfires and/or low fuel pressure, I never felt any stumbling nor ever had hard-starting problems. I replaced the oil filler cap & seal (didn't help with the codes, but my beauty cover stays clean now), and the exhaust cam position sensor during that period (P0365 came up, so I replaced that sensor immediately), and then was at an impasse, wondering what to try next.

Since the P0171 & P0174 codes (and the corresponding SES/CEL) were being triggered by extremely high fuel trim numbers, I installed a cheap $23 MAF sensor (suggested by X5chemist, which has kept the fuel trims lower, and I don't have the lean codes anymore.https://xoutpost.com/1220730-post15097.html My original Siemens/VDO oem MAF sensor must've been under-reporting airflow (despite several tries with MAF cleaner), because the fuel trims immediately dropped into a more normal range, and have stayed low for 6+ months, so far (X5chemist is still using his cheap MAF, for over a year).

Concerning the small leak in "the accordion that goes between the ram air scoop and the intake box", are you referring to this tube?
Name:  air intake boot.JPG
Views: 31
Size:  45.5 KB air intake boot

Mine doesn't seal very well (another cheap Amazon replacement), but since it is placed before the MAF sensor measures airflow, then it can't be the problem. The cheap MAF may just be covering up for a yet-undiscovered underlying problem causing the lean codes, but until I find them, I'm happy to be (semi) code free. It passed emissions inspection last month!
__________________
'01 BMW X5-E53 3.0i (born 7/13/01)
topas-blau, Leder-Montana grau,
my new favorite project car

Plus four GM vehicles, Daily Drivers, and modified trucks for hauling & camping:
3 Chevys:
'09 HHR Panel LS 2.2L,
'08 Cobalt Coupe LS 2.2L,
'04 Silverado 2500HD WT Reg. Cab
+ a '98 GMC Sierra 1500 Ext. Cab

- and 20 others, now gone, that I've had over the last 57 years (not counting the stillborn "1965 ChevyII altered/gasser project")
Reply With Quote
  #5  
Old 11-22-2022, 08:11 PM
Member
 
Join Date: Feb 2019
Location: Caroline County, MD
Posts: 239
lkv0315 is on a distinguished road
Quote:
Originally Posted by workingonit View Post
I fought the same codes for 7 months (along with random misfire/low fuel pressure codes) constantly checking for vacuum leaks (none found) or a fuel pressure loss (none found), in vain.https://xoutpost.com/bmw-sav-forums/...-codes-me.html Though the codes showed misfires and/or low fuel pressure, I never felt any stumbling nor ever had hard-starting problems. I replaced the oil filler cap & seal (didn't help with the codes, but my beauty cover stays clean now), and the exhaust cam position sensor during that period (P0365 came up, so I replaced that sensor immediately), and then was at an impasse, wondering what to try next.

Since the P0171 & P0174 codes (and the corresponding SES/CEL) were being triggered by extremely high fuel trim numbers, I installed a cheap $23 MAF sensor (suggested by X5chemist, which has kept the fuel trims lower, and I don't have the lean codes anymore.https://xoutpost.com/1220730-post15097.html My original Siemens/VDO oem MAF sensor must've been under-reporting airflow (despite several tries with MAF cleaner), because the fuel trims immediately dropped into a more normal range, and have stayed low for 6+ months, so far (X5chemist is still using his cheap MAF, for over a year).

Concerning the small leak in "the accordion that goes between the ram air scoop and the intake box", are you referring to this tube?
Attachment 82811 air intake boot

Mine doesn't seal very well (another cheap Amazon replacement), but since it is placed before the MAF sensor measures airflow, then it can't be the problem. The cheap MAF may just be covering up for a yet-undiscovered underlying problem causing the lean codes, but until I find them, I'm happy to be (semi) code free. It passed emissions inspection last month!
Yes, that is the intake boot I was talking about, and I genuinely figured exactly what you said, since the trim would be calculated using MAF data.

How confident are you that this new sensor isn't just less accurate than the OEM ones? It seems strange that the sensor would just read badly, but maybe I just don't understand the way a MAF functions internally that would make it deteriorate. But given it's a cheap solution I'll likely give it a try.
(because if that's not the issue, replacing it wouldn't fix the code??)

And I don't know what you mean by extremely high trim values, according to my OBD app's readouts, my long term trim maxed at 11.96% and short term maxed at 15.2%, and I don't know what percentage actually triggers the code. Would you define those values as very high, or just marginally high?

Thanks for the reply, I'll be sure to go read the thread you linked to see if theres any other relevant information to glean from it!
__________________
2005 X5 E53, 167k Miles: Kenwood DNX893S Head Unit, Mud Flaps (Rear Only) , Rim Shopping(WIP), Full Spectrum RGB Halos,
Reply With Quote
  #6  
Old 11-22-2022, 09:30 PM
workingonit's Avatar
Member
 
Join Date: May 2021
Location: DFW Texas
Posts: 468
workingonit is on a distinguished road
stuck in the middle of the problem, with no 100% cure in sight

Quote:
Originally Posted by lkv0315 View Post
...

How confident are you that this new sensor isn't just less accurate than the OEM ones? It seems strange that the sensor would just read badly, but maybe I just don't understand the way a MAF functions internally that would make it deteriorate. But given it's a cheap solution I'll likely give it a try.
(because if that's not the issue, replacing it wouldn't fix the code??)

And I don't know what you mean by extremely high trim values, according to my OBD app's readouts, my long term trim maxed at 11.96% and short term maxed at 15.2%, and I don't know what percentage actually triggers the code. Would you define those values as very high, or just marginally high?....
I stated that I'm not sure whether or not the new MAF isn't just covering up the real underlying problem, by over-reporting airflow instead of under-reporting it. I got the cheap MAF just for testing purposes, as I didn't want to buy another OEM sensor for $$$$, if it wasn't needed. I'm still keeping the original in the trunk.

A fellow forum member promised to send me a "tested good" Siemens MAF for testing, but never did. As it stands now, I'm using the cheap MAF until
  • 1) I get a moderately-priced new one (maybe Bremi or Hella??) for further testing, but a "tested good" Siemens would've been better-or-
  • 2) the cheap MAF fails, justifying (to my wife) that I need a new Siemens, desperately!!

From what I've read on many sites, the total of short-term and long-term fuel trims will trigger a SES/CEL when the total exceeds +/- 25%. Your example of (+11.96%) added to (+15.2%)=(+27.16%), which will trigger the SES/CEL. Presently, on my last drive, my long-term trims are about (+3.16) each, give or take, but they are being cancelled out by negative(-) short-term numbers, tending towards a total of zero.

Since my long-term trims never seem to get to zero (my '04 Chevy 2500HD 6.0L has rock-steady long-term readings of zero) I must assume that
  • 1) my DME hasn't yet gone back to the fuel map "zero" (coded into memory), or
  • 2) the not-yet-discovered underlying problem still exists.
Hence, my reticence to declare the problem fixed, or that the cheap MAF is actually the final solution.
__________________
'01 BMW X5-E53 3.0i (born 7/13/01)
topas-blau, Leder-Montana grau,
my new favorite project car

Plus four GM vehicles, Daily Drivers, and modified trucks for hauling & camping:
3 Chevys:
'09 HHR Panel LS 2.2L,
'08 Cobalt Coupe LS 2.2L,
'04 Silverado 2500HD WT Reg. Cab
+ a '98 GMC Sierra 1500 Ext. Cab

- and 20 others, now gone, that I've had over the last 57 years (not counting the stillborn "1965 ChevyII altered/gasser project")
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On





All times are GMT -4. The time now is 11:10 AM.
vBulletin, Copyright 2022, Jelsoft Enterprises Ltd. SEO by vBSEO 3.6.0
2017 Xoutpost.com. All rights reserved. Xoutpost.com is a private enthusiast site not associated with BMW AG.
The BMW name, marks, M stripe logo, and Roundel logo as well as X3, X5 and X6 designations used in the pages of this Web Site are the property of BMW AG.
This web site is not sponsored or affiliated in any way with BMW AG or any of its subsidiaries.