wont crank now

[BigDaddyDupree]

i just purchased a 200 avalanche and the previous owner installed a diablo sport programmer but didnt like running premium gas so set it back 2 stock, i attempted to install it back and it came up to the point where it said 100 percent complete and said error, now the truck will not start or do n e thing. whats the deal?

[mikel]

Not sure?
Sounds like a possible voltage issue.
Was there anything on during the install?

[69Zeleven]

What version are you using? Do you have the 6.0 engine?