LB7: Engine Over Boost

[mtrcontrols]

I have a 2004 Chevy Silverado 2500 HD, w/ Duramax 6.6-LB7 & 5 speed Allison transmission I bought new 8 years ago.
The last two times I towed my 9,000lb 5th wheel, I got a [ check engine light ] came onand both times it was a [ Engine Over Boost Condition ]. Condition was apx 60 mph with 9k lb. trailer in tow with a 5% up grade hill and accelerating to pass a tractor / trailer. No loss in power, just a warning light!
The only thing I have change this year on it is I went from a stock 3 ½” exhaust to a 5”. I have been using a Super Chip programmer on medium performance for the past 5 years now.
Does anyone know what could be causing this? And what do I need to do to control the situation?

 

[AubleAK]

Malfunctioning wastegate maybe?

 

[SSchmi5519]

It is a parameter in the ECM. There is an amount that boost is allowed to be +/- the desired. There is also a timer table that goes along with them.

If the boost is above (your case, overboost) or below greater than the amount of time in the timer table, this code will set.

Just thought it would help knowing why the code pops.

Turning the Superchips back to stock will solve the problem.