P0880 and U0101

[AZlml]

After checking grounds, continuity at pin 9 and 69, and following the harness for any wiring issues I don't know where to go next. What should I be checking or seeing for input or signal voltage to the TCM? Google search shows pins 75 and 54 are 5volt and 77 is input, is that correct? Any help is appreciated. Trans is stock, no tune.

 

[Tothemax]

did you check the ground g102 on the driver side of the engine block its the one closer to the front. there is a gm bulletin for those codes and a bad ground at g102

 

[AZlml]

Yes I got that one, the single wire right behind it, the one below the driver's door and the back of the engine to the firewall on drivers side.

 

[Ron Nielson]

Free wiring diagrams available at http://www.bbbind.com/tsb-wiring-diagrams/

The source I like is ALLDATADIY - about $35 for 5 years access. Wiring diagrams, wiring connector diagrams, TSB's, DTC's and lots more. Well worth the money in my opinion. If you work on your truck, you need one of these (or something similar).