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Thread: LBZ P0299 Help

  1. #1
    Potential Tuner
    Join Date
    May 2015
    Posts
    8

    LBZ P0299 Help

    I am trying to figure out what i need to edit to change the threshold values so that i will no longer get DTC P0299 overboost/underboost. I have searched all the threads i could to find to get a direct answer to this question with no avail. If someone could just tell me in short or point me in the right direction as to how to figure this out so that i dont get the p0299 and go into limp mode that would be awesome. If this has been covered and i just missed it could someone please post the link as to where to find the info? Thanks.

  2. #2
    Did you try setting the DTC to MIL off? Under engine diagnostics/DTC's. That worked for me on P0234 overboost.
    1999 s10 blazer trailblazer edition nv3500 swap
    2006 GMC ccsb 4x4 duramax/allison

  3. #3
    Potential Tuner
    Join Date
    May 2015
    Posts
    8
    Yes. That will only keep the MIL light from indicating there is and issue, however the truck still goes into limp mode.

  4. #4
    Tuner in Training
    Join Date
    Apr 2015
    Location
    Clearwater,FL
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    21
    Is the truck stock or have you tuned the truck? What mods have you done to the truck, cai, exhaust? Depending on how your truck is configured, I would offer different results on how to fix your code problem. If your truck is bone stock, I would say to check your turbo waste gate solenoid and make sure it's not sticking or check your turbo resonator and make sure it's not cracked. Both of those problem's are pretty common on those trucks and will cause that code. If you have done tuning and have put a bunch of mods on the truck and are certain that the waste gate and resonator are in good working condition and the truck is free of any boost leaks you could log boost and see in what area it is throwing the code and raise the limits in that area to where it won't throw the code. MAF<MAP correlation. I have also fixed a few chaffed wiring harness' in these trucks where any kind of altering/tricking the pcm wouldn't of worked.
    05 Excursion 6.0
    14 Silverado 4.3

  5. #5
    ^^ This is a variable vane boost control system Chris. No waste gate controls will apply here. Similar concept but very different strategy.

    Blackronin22: Where in the mapping is the overboost being set? (part throttle, medium load/medium throttle, wot, etc etc). Also, and probably most importantly, where do you have all your desired boost tables and max boost limit set? Are you just cranking your vane positions and shooting for the moon or is everything set to compliment one another? Assuming all your desired boost vs vane position tables jive, another thing to keep in mind is setting your minimum vane position too high can result in an overboost condition in areas you might not normally expect to set that condition due to the ecm losing it ability to negatively counter a looming overboost situation.
    09 Cobalt SS - E47+EFR6758 =

    07 Silverado ECSB LBZ Duramax - Bunches of goodies