Trans is popping codes

[Teahead]

Any ideas?

 

[Happy Hummer]

The code gives you your fault and probable problem and solution.
Speed sensor or wiring to pcm/ecm. Start here and broaden as need.

 

[Alpha X]

I read somewhere that these codes can be caused by a faulty ground inside the transmission. To fix it you need to pull the transmission out. An alternative to pulling out the transmission is to splice into the transmission ground wire to create a new ground to the frame. I don't remember where I read that, I think it was on one of these hummer forums. This is a suggestion for what to investigate to confirm the above is actually true.