LB7 Overboost p0234

Power Crazy · 01-04-2008, 12:25 PM

Hey guys, new member but a long time reader.. I've read and searched here and other forums for a solution to the P0234 code on a Duramax LB7 and have seen alot of people with the same problem but havent been able to find a solution yet.. Here a quick rundown of what I have and whats going on..

2001 Chevy 2500HD LB7 Duramax 6.6, 165k miles,
4" Exhaust
Edge w/ Attidude Monitor
Air Hog K & N air filter

I have owned the truck since 2005, when I bought it it allready had the 4" exhaust.. It's ran without any problems until recently.. In the last 4 months i've had the fuel rail replaced (old one was leaking), injectors checked and the Edge installed.. Now when I get on it or am going up an incline at around 70 or 80 it will go into limp mode and shut me down to 65 for about one minute and then will regain power and run smooth until I get on it again or go up an incline again.. First thing I did was change the fuel gilter.. I've tried it in all power settings on the Edge and it comes up on all of them.. It will pop up the SES light sometimes but not allways.. I pulled the codes and "P0234 and P0101" came up.. P0234 is an overboost and P0101 is Mass air flow.. The P0101 is not really a concern being it has an aftermarket breather and is expected, but id like to figure out what the P0234 is because it get a little annoying being shut down like that.. Ive seen on the net that they sell a "P0234 fooler" that fools the PCM into thinking nthing is wrong but i'd prefer to find and fix the problem rather than just "fool" it.. I took it to the Chevy dealer and he claimed that if I took all the aftermarket parts off it it will fix the problem.. Well I doubt thats gonna happen, I didnt buy them to decorate the garrage.. Any help is appreciated.. Thanks

**ob_1jr** · 01-04-2008, 05:55 PM

Your problem is probably more from the P0101 (mass air flow sensor) than the P0234. Check your air filter and intake to make sure it is sealing good. Next....I would throw that k&n out and get a different filter.....the oiled filters especially the k&n oil tears up the mass air flow sensor. Next I would pull the mass air flow sensor and clean it with some contact cleaner....don't touch the resistors, but just spray it off. I have had P0234 a few times, but it never made me lose power. I got it with a p0101 and I lost power...found part of my AFE intake came disconnected from the resonator (the 6.6 plastic thing). Also, the P0101 is not expected with the aftermarket intake....although k&n intakes have had that problem.

Power Crazy · 01-04-2008, 08:51 PM

Thanks ob_1jr, I have an aftermarket AEM cold air that i'm gonna put on probably tomorrow.. I'll check the MAF sensor and clean it also before I put it on the other intake tube.. I'll double check to make sure everything is sealing good before I close the hood.. Thanks again..

bearden auto · 01-29-2008, 04:57 PM

My truck does the same thing and I have replaced almost the whole fuel system and alot of the sensors.

Power Crazy · 01-29-2008, 07:44 PM

Well, iv'e changed intakes to a no oil afe intake, cleaned MAF sensor, tightened all intake clamps, any other ideas on what could be causing this.. My guess is that it has to be the Edge, I called them awhile back and they said that there is no fuel limp on my year, just a transmission limp but I could send the chip in and they would check it out.. I might try that next. I'll keep you all posted on what i find out..

mikeshotrodshop · 01-29-2008, 07:51 PM

Quote:

My truck does the same thing and I have replaced almost the whole fuel system and alot of the sensors.

Ouch!!!!!! Might I suggest purchasing a repair manual instead of throwing parts at the problem. I say this to help, not to be facetious. The book may seem expensive but not as much as the parts did that didn't reverse the problem. I have been in the repair business for a long time (since birth) and would always verify my suspicions before I condemn a part. With that said - Power crazy, you may want to check the turbo output. If this is high you will also get a high reading from your MAF and it will produce a CEL complaint. Do you have a scanner or can you borrow a friends? I would start with verifying the boost pressure by means or a scanner of gauge. I would rely on the gauge before the scanner due to the reading is only as good as the sensor (which could be faulty).

You may also want to make friend with the guys at the local truck shop. They may be able to help guide you in the right direction and maybe help diag the problem for free!!!

Best of luck and keep us posted on the progress :0)

bearden auto · 01-30-2008, 08:30 AM

The condition happens at about 17 pounds of boost,2400 rpms, 60 mph not all the parts were replaced chasing this problem the truck has 152,000 on it and some of these part just simply were worn out. We had the engine out because it blew a head gasket and hydro-locked bending the #6 rod and replacing the pump and injector at this time I actually got the local dealer to warranty the injector and i istalled them during the rebuild.