operating system questions

[lockner13]

What i need to know is i have an 01 lb7 truck that is a 2wd, i completely swapped in an 01 electronic shift 4wd setup out of a parts truck wiring harnesses and all. I need to know if the tunes need changed between 2wd and 4wd. It all works except if you shift to 4 lo it will go into a limp condition and not let you shift to 2wd again until you reset the ecm. It throws a vss code. Any help would be great

[badbowtie]

Yes from my understanding there is a tables that you probably dont have or are not set right for the 4lo. I would look at a 4x4 tune and compare and see what you are missing. Or post your tune and I am sure some one can help you out. There is a couple stock tunes you can download in tune repository.