LEAN CODE P0171/P0174

2001 BMW X5
112,086 MILES • V8 • AWD • AUTOMATIC
Avatar
MYSWEETX5
  • MEMBER
  • 16 POSTS
[img:aa3b1a9b5b]http://www.2carpros.com/forum/automotive_pictures/504541_2001_X5_44i_1.jpg[/img:aa3b1a9b5b]

Everyone knows that there's alot to check with when it comes to these two lean codes: (P0171/P0174). But some vehicle may have very specific location as usual for this particular issue. And I wonder if anyone ever experienced this lean problem on the same car mentioned above, how do they resolved it. And how do I test the air mass sensor to see if it's working properly after cleaning it.
Aug 26, 2010 at 1:05 PM
Advertisement
Avatar
DOCHAGERTY
  • CERTIFIED EXPERT
  • 9,603 POSTS
Hello,

When you have a lean code 9 times out of 10 it is the MAF sensor. Here are two guides and a video on how to change the MAF and other things to heck for the lean condition.

https://www.2carpros.com/articles/repair-lean-mixture-codes-p0171-or-p0174-on-some-manufacturers

and

https://www.2carpros.com/articles/how-to-replace-a-mass-air-flow-sensor-maf

Cleaning the MAF doesn't really work when the sensor is to far gone.
Aug 26, 2010 at 7:11 PM
Avatar
JERRYGEARLD
  • MEMBER
  • 0 POST
Thanks for this post I got a new MAF sensor for $97.00 and the problem is gone! I love this site.
Jan 15, 2019 at 7:14 PM
Advertisement
Avatar
MYSWEETX5
  • MEMBER
  • 16 POSTS
when i scanned my the vehicle with my computer, those code appear p0171/p0174 lean codes but when i checked further, the computer mentioned: (heater catalyst not ready, (egr valve not supported) (a/c refrigeration not supported)

what is that mean because i have 4 new 02 sensors.
Jan 15, 2019 at 7:14 PM (Merged)
Avatar
RASMATAZ
  • CERTIFIED EXPERT
  • 75,992 POSTS
Lean fuel condition could be caused by one of the following below:

1.Vacuum leaks
2.EGR and PCV valve.
3.Low fuel pressure.
4.Dirty fuel injectors.
5.Mass Air Flow Sensor.
6.Oxygen Sensor.
Jan 15, 2019 at 7:14 PM (Merged)