P0299 underboost on LMMs KILLING ME

[Boost]

It seems to me since I updated about a month or two ago all of a sudden I am having major catastrophic issue with my customers constantly going into limp mode because of P0299. I would NEVER blame the update and I am not. Just scientifically / logically I have never had issues with first 130+ customers and now I do. I would rather suspect my laptop is going bad or I am crazy. So please help.

Situation #1 (guy has not called so not the most pressing issue):
I did a simple delete on an LMM van and it went great, If you see a video of the burnout it does you will flip. It is brutal and ran great. But randomly throws 299 and limps limps limps. For a month I assumed it was totally my fault (still think it is) or a mechanical issue. But after trying everything, I contacted the best tuner in the world I can think of for help and he was so kind and awesome that he provided a tune. Power delivery and smoothness wise I must say it runs 100 times better than my tune. But guess what it does the same thing. Shocking but he hasn't called and I have a bigger emergency.

Situation #2 (must fix or die lol)
'09 Truck, kind of beat up but very nice, simple delete and tune. Limps / smokes / jerks / 299. I have tried EVERYTHING. Even put in a DSP5 switch to see if a custom OS would help. Remember I have kind of done this before... Limps 299 / undriveable. Even stock with delete only it limps 299. I am at my wit's end, he is letting me borrow the truck for two days and basically walking, and expects a fix. I am attaching the tune and some logs of it limping.

I know it could be some really stupid oversight on my part or my tunes have become corrupt. I even tried a professional bought tune in it from the lead diesel tuner of a big name company I dealt with in the past and same thing. Please, help.

Note: I stopped the logs right after limping so it occurs at the end.

[Mitco39]

on the 09 truck, have you tried returning it to stock and seeing if it limps? If you get a emission limp then just do a delete on it but leave everything else alone. Does it still limp? You could try selecting the whole DTC table and just going do not report in all the columns. Fire up the truck and see what you got. Ive had issues with codes before and I have noticed that some codes are not actually what they are in the DTC list. For example the AC pressure circuit code is somehow related to the ECT #2 sensor code. I would start with that and try bringing back the codes you want to keep a few at a time.

Worth a shot at this point.

Goodluck

[Boost]

on the 09 truck, have you tried returning it to stock and seeing if it limps? If you get a emission limp then just do a delete on it but leave everything else alone. Does it still limp? You could try selecting the whole DTC table and just going do not report in all the columns. Fire up the truck and see what you got. Ive had issues with codes before and I have noticed that some codes are not actually what they are in the DTC list. For example the AC pressure circuit code is somehow related to the ECT #2 sensor code. I would start with that and try bringing back the codes you want to keep a few at a time.

Worth a shot at this point.

Goodluck

Thanks for the reply and the suggestion. Yes, I have returned it to stock"ish" (since it DSP5 and DPF delete I can only put the power level stock since custom OS is irreversible and I must keep the delete settings or it will limp for that. Still 299 / reduced power. I will try knocking off ALL the codes, as you said it is worth a shot at this point especially if they may be inaccurate.

[Boost]

It couldn't possibly have anything to do with the EGR right? At this point I cannot afford to guess but I usually block / delete them and I heard a rumor that the push open with boost even when disabled.

[THEFERMANATOR]

I've full flashed BOSCH controllers(LBZ's) back to single tunes before without trouble.

[Boost]

Gonna try that as well. But are you sure it's not still stuck DSP5 custom OS forever - just not responding to switch and / or all 5 tunes are stock??

[Mitco39]

You can full flash in any LBZ/LMM OS into the E35B/E35A controller. I have done every combination with no ill side effects. You wont harm the controller as long as its OS from 06+ to 2010. I strongly suggest taking this tune, doing ONLY the delete on it. Not touching anything else at all. And full flashing it into the controller. I have been able to fix pretty much any issues I had from starting from a fresh base (even if for whatever reason the tunes worked just fine on trucks previously).

http://www.tunefiledepot.com/calibrations/stock/Chevrolet/2009%20Chevrolet%20Silverado%20Truck%20Automatic%2 0LMM%206.6%20Litre%20(12628594).tun