GM
Type:
    Powertrain - Manufacturer Controlled DTC - Manufacturer Controlled
Description:
    Internal Mode Switch - No Start (4T65 - E Transmission)
Cause:
    Key in Start (crank) position, system voltage from 9-18v, then the PCM detected an invalid combination of Internal Mode Switch signals, or a set of signals that indicated a transitional state between gear positions, condition met for 0.5 seconds.