Results 1 to 12 of 12

Thread: P140B code

Hybrid View

Previous Post Previous Post   Next Post Next Post
  1. #1
    Join Date
    Jan 2006
    Location
    South Milwaukee, WI
    Posts
    245

    Default P140B code

    I'm getting a P140B code on a L5P Dmax, suggesting the EGR valve response is slow. Now, this code is being read on an older model Edge monitor which was originally used on my old LB7 2001. I have NO check engine light at the moment. I can clear it, but it reappears the next time I read the DTCs. Should this be something to be concerned with or just a false alarm?
    "Chessy56"
    So. Milwaukee, WI
    '01 2500HD, LB7, ~440K miles
    "Stock" engine. Dual fuel filtration system with Kennedy lift pump, BF Goodrich Commercial T/A Traction tires (sold to a dude from Texas- it's living a warmer life just fine down there now!).

    '17 2500HD, L5P (Happy Birthday/Merry Christmas to me!!!) Currently bone stock, 120K miles.

    "Socialism is a philosophy of failure, the creed of ignorance and
    the gospel of envy. Its inherent virtue is the equal sharing of misery."
    Winston Churchill

  2. #2
    Join Date
    Dec 2002
    Location
    Teton Valley, Idaho
    Posts
    1,873

    Default

    Do you trust your local parts store guy enough to let him put a (hopefully newer) reader on your truck to see if he can pull the same code?
    Edit: On a 2017, wouldn't the factory warranty be valid enough to bring the truck to the dealer and let them sort it out?

  3. #3
    Join Date
    Jan 2006
    Location
    South Milwaukee, WI
    Posts
    245

    Default

    I can ask one of our guys at work who are product support engineers if they've got a moment to look at it. If the check engine isn't on, I wouldn't have known about it and am thinking it should be looked at, but it's not suggesting immediate action. I saw this code earlier in the week, and the check engine lamp did come on. However, after the 3rd restart, the lamp did not return and I've put some 450 miles on it since- and still no check engine lamp.

    Thanks for the reply BTW...
    "Chessy56"
    So. Milwaukee, WI
    '01 2500HD, LB7, ~440K miles
    "Stock" engine. Dual fuel filtration system with Kennedy lift pump, BF Goodrich Commercial T/A Traction tires (sold to a dude from Texas- it's living a warmer life just fine down there now!).

    '17 2500HD, L5P (Happy Birthday/Merry Christmas to me!!!) Currently bone stock, 120K miles.

    "Socialism is a philosophy of failure, the creed of ignorance and
    the gospel of envy. Its inherent virtue is the equal sharing of misery."
    Winston Churchill

  4. #4
    Join Date
    Jan 2006
    Location
    South Milwaukee, WI
    Posts
    245

    Default P140B diagnosed....

    OK- P140B confirmed via TechII. One of our product support engineers @ GM noted the code in the history; my Edge was reading it correctly. Took it to the dealership and further diagnosis suggested that there was "too much air flow" at the EGR and hence, the code. However, I do recall that we got a bit of snow on the day the SES lamp was set (I probably pushed some into the duct when I was cleaning off the hood). My tech mentioned that the air induction system facilitates an accumulation of snow on the air filter- which should've restricted the air flow (odd that "too much" flow was being reported). I guess GM hasn't addressed the potential for snow to be sucked into the air induction intake yet (short sighted, IMO).

    I tried getting a replacement air filter to keep in the event another blockage occurs. Sadly, no one carries one- not Auto Zone, CarQuest, NAPA nor my Chevy dealership! No dealership in my general area stocks one! You'd think that after 1 year since introducing the L5P, dealers would have one of these on hand. Also, the owner's supplement for the Duramax has a GM p/n 84030829 for this filter; however, my dealership states the number should be 84130829- a typo in the owner's manual as well?

    I was thinking about a K&N replacement element, but that faces the same risk for getting plugged with snow too if GM doesn't address this issue. Just a heads up for you L5P owners operating in cold/snowy climates....
    "Chessy56"
    So. Milwaukee, WI
    '01 2500HD, LB7, ~440K miles
    "Stock" engine. Dual fuel filtration system with Kennedy lift pump, BF Goodrich Commercial T/A Traction tires (sold to a dude from Texas- it's living a warmer life just fine down there now!).

    '17 2500HD, L5P (Happy Birthday/Merry Christmas to me!!!) Currently bone stock, 120K miles.

    "Socialism is a philosophy of failure, the creed of ignorance and
    the gospel of envy. Its inherent virtue is the equal sharing of misery."
    Winston Churchill

  5. #5
    Join Date
    Apr 2001
    Location
    CA
    Posts
    13,573

    Arrow

    Likely just a sensor anomaly, due to the snow, although any number of conditions could cause it. This condition was common with early LB7's when (cheaper) aftermarket or homemade intake plumbing was installed. The change in flow turbulence causes the MAF to misread the actual air volume. Some higher, some lower. The correct volume would still flow, but the sensor simply didn't read it correctly. The emission system sensitivity of the later models would certainly detect the slightest variation. The soft code (no SES lamp) may indicate the values are nearing a threshold value, but not quite crossing it.
    1985 Blazer 6.2
    2001 GMC 2500HD D/A
    dmaxmaverick@thedieselpage.com

  6. #6
    Join Date
    Feb 2000
    Location
    Montana
    Posts
    11,382

    Arrow

    Whether it's the variable vane turbocharger or variable position EGR, the position sensor can sometimes drift out of calibration. I technician with a Tech II scan tool can test the EGR system and re-calibrate the position sensor. The Tech can also exercise the related components to verify correct operation. Something to keep in mind.... Jim

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •