02 gmc yukon tried connection 3 and program 3 but didnt program. Should i down grade it to 4.06?

Question

I have the evo all updated to the latest software, which maybe the problem.

Answer 1

70.18 is the go to firmware on J1850 databus GM vehicles. If 4.06 is available for your module, you can always try it but 70.18 is the "same" thing.

 

If the voltage on the J1850 is under 2Vdc, that would be one reason programming is failing.

You can also try grounding the EVO-ALL and your remote starter to PIN 4 of the OBD connector instead of using a chasis ground.