I am getting a P0234 engine overboost condition code just about everyday when I am crusing at highway speeds. Usually flat ground with no load. I am leaning more towards a bad sensor or a wire rubbed through and grounding out. Happens when stock or with my efi tune. I am not about to take my truck to the dealer for this even though the truck is still under warranty. Does anyone have the trouble shooting procedure for this code. I am thinking right now that I have a wire rubbed through and the sensor is reading out of range.

i'm having the same problem with 04 1/2 lly. at the shop now

Let me know what they come up with.

replaced Boost sensor...... no problem for 2 days. then, overboost again.
boost is reading 25 to 27 on juice attitude moniter. then 0 without any change in throttle position. tons of brown smoke , not the usual black fog , significant loss of power
gonna take it back to him after thanksgiving

removed the boost stick and extension on 11/27. No problems since. hesitantly thinking it may be fixed.

I had the same problem except I was getting an underboost code. Pulled out the boost stick and swapped it for a new one and it solved the problem. You and I aren't the first to notice this and it seems that boost sticks will just $hit the bed with no warning and then you're trying to find a problem that doesn't leave a trace. Seeing as how its just a solid state circuit board, if it doesn't work its not going to tell anyone but it'll sure screw your truck up.

Try diablo extreame power puck. It has boost fooling on d max. I stacked a power puck with ppe standard tunner, pushing 35lbs of boost no codes.