https://www.dtcdecode.com/Chevrolet/P0658

 

For the P0658 code on your 2007 C5500, check the wiring and connectors to the transmission control module (TCM), as damage or corrosion could cause the issue. If the wiring is fine, consider testing or replacing the TCM itself. Also, verify voltage and resistance in the actuator wiring (shift solenoids) and consider checking or reprogramming the ECM/PCM if the problem persists.

 

That code seems to be gone. Tested all pins for power and ground at tcm, now having codes p0751, p0756, tested harness from tcm to trans for those solenoids. Also removed pressure switch. Tested it. Have all highs and lows, perhaps valve body issues?

 

Also should add. Using a friends tech2 now all this too