It means you are getting less boost than what you are demanding. You can either log and find out where in the B2204-B2209 tables this is occurring and demand less boost in that area, or your can cheat and change C0804 to allow more room for error.
I do believe so because when I had my boost controller set up and didn't have my egr blocked it would throw it all the time. Do you have a ppe controller? Even after I blocked the egr it would put up on a cold start within a couple minutes if it was turned up any
OK, this is the story.
Back when the LLY came out, and people started putting on either aftermarket aircleaners, EGR blockers, or exhaust systems, AND they went driving in the mountains, the infamous P0299 Underboost code came up. It is a performance limiting code, so it was important to resolve. It was often accompanied by MAF codes.
What was happening, is that since you altered the air flow going in and out of the engine, the MAF sensor reading + the baro sensor reading, did not line up with the boost sensor reading. So the GM computer "guesses" at what is wrong, and it figured there was a problem with the boost. The boost sensor itself still was reading OK, the turbo was fine, but the MAF reading was different we found.
So it is unlikely that there is really anything wrong with your truck UNLESS you are bone stock.
The easy fix is to increase the boost error limits to 15 psi, IIRC, as Othergirl posted above. Trying to "recurve" expected boost is fine, editing the MAF sensor scaling, etc, will all git-er-dun but the boost error limit is the most reliable way of killing it.
Back when the LLY came out, and people started putting on either aftermarket aircleaners, EGR blockers, or exhaust systems, AND they went driving in the mountains, the infamous P0299 Underboost code came up. It is a performance limiting code, so it was important to resolve. It was often accompanied by MAF codes.
What was happening, is that since you altered the air flow going in and out of the engine, the MAF sensor reading + the baro sensor reading, did not line up with the boost sensor reading. So the GM computer "guesses" at what is wrong, and it figured there was a problem with the boost. The boost sensor itself still was reading OK, the turbo was fine, but the MAF reading was different we found.
So it is unlikely that there is really anything wrong with your truck UNLESS you are bone stock.
The easy fix is to increase the boost error limits to 15 psi, IIRC, as Othergirl posted above. Trying to "recurve" expected boost is fine, editing the MAF sensor scaling, etc, will all git-er-dun but the boost error limit is the most reliable way of killing it.
On a realated note, I get a P0299, but ONLY when the truck kicks up to elevated idle when it's cold. I've been pulling the freeze frame data each time I get it, but haven't checked it yet. My intake is a stock 06 intake, EGR fell off, and I have the GM update that includes the calibrations for the 06+ airbox. Ideally, I'd like to fix it without "compromising" the test it's self, so if I actually DO have a problem, it's detected. Thoughts?
I've been getting this code since I put my nozzles in. like said usually in the first few minutes after a cold start. Happened once warm though while cruising the interstate.
To fix it without "compromising" the test you would need to log it and pull boost out of areas of the table where it cannot meet your demands.
So i am helping a friend that has an 05 lly. he has this code p0299 after intake and exhaust. so i should set his C0804 table to 15 all the way down? he is running the basic 20/20 tune for lly's. thanks in advance.
steve
steve
Just open up the allowable boost error table. That always fixed it for me. Don't remember the table #.
Thanks Pat. c0804 is "underboost limit". must be that table? I don't see "allowable boost error".
The same thing happens to me as well when the elevated idle kicks in,it will run in high idle for a while but then throws a code and goes back to idle. I have found the culprit to be in the P2225 turbo vance position minium table. I have my table modified to 5% vane position at idle to get an exhuast rumble. If I put it back to stock values I dont get the underboost code anymore. I have heard the LLY E60 PCMs dont like some of the programming changes you make with some tables and it does quarky stuff. My friend has a LMM and his truck works fine with the same settings as mine. Though it is rather confusing since the high idle doesnt reside in that part of the table I modified.
I use to get that code also from high idle. give me a bit and ill figure out what I did.
search that code on here in the mean time.
search that code on here in the mean time.
I've got the P0299 code 3 or 4 times in the last week or so. I have a EGR Blocker Plate installed and mild tunes from Idaho Rob at ATP. What is the cure for this and aside from saying low boost detected what does this code mean(like what part am I going to need to change?) I haven't noticed any problems or issues with the truck even when the code is present. Is this the first sign of needing the Turbo Vane Position Sensor replaced?
Turbo Booster code
My truck will throw a turbo booster code when I'm pulling a load every now and then, mostly on long hauls. I have a 2002 2500hd duramax with getting close to 269k miles on an original engine and transmission. even when the engine light is on when it's throwing this code, it pulls fine and still runs cold. just don't like seeing that light on when I got 800 miles left in a trip. anything I can do to help keep the light from coming on and throwing that code? I wanna say the last time it came on it was the P0299 code, but this time the light went off before I could plug it up.
My truck will throw a turbo booster code when I'm pulling a load every now and then, mostly on long hauls. I have a 2002 2500hd duramax with getting close to 269k miles on an original engine and transmission. even when the engine light is on when it's throwing this code, it pulls fine and still runs cold. just don't like seeing that light on when I got 800 miles left in a trip. anything I can do to help keep the light from coming on and throwing that code? I wanna say the last time it came on it was the P0299 code, but this time the light went off before I could plug it up.