I have read here on the forum that the 06 LLY has a Bosch ECM and other changes. My truck is an 05 LLY with a build date of 04/05 and I believe it has the Bosch electronics as well, due to the fact that the box located above the right hand valve cover is labeled Bosch. My question is did GM change to the later version of the LLY at the end of the 05 model year or is this just a change in the electronics? Also will current LLY programmers work with this change?

I would think that if that box is above the valve cover, then it be more than likely a control module for the injectors and not the entire ECM itself. It is a seperate piece that is only for injectors.

However, I am no expert, just a thought. Mine was built in 7/05, but I haven't paid any attention to that, so I don't know what it has. I will look when I am under there again.

The injector control module proves it's a "normal" LLY, and that the existing modules and programmers will work.

The 2006's have Bosch PCM's and are incompatible with normal LLY's.