Why does the Volkswagen transmission U0101 fail to start?

[Paige]

Volkswagen transmission trouble code U0101 causes the vehicle to fail to start due to loss of communication with the Transmission Control Module (TCM). Additional information: 1. Trouble code analysis: Modules connected to the high-speed GMLAN serial data circuit monitor serial data communication during normal vehicle operation. Operational information and commands are exchanged between modules. Pre-recorded information in the modules specifies which data needs to be transmitted between the serial data circuits of each virtual network. The receiver module monitors this information and uses some periodic messages as indicators of the transmitting module's operational status. The monitoring timeout is set at 250 milliseconds. Each message contains the identification number of the transmitting module. 2. Conditions for setting the diagnostic trouble code: The ignition switch is in the "Run" position, and communication with the transmission control module is lost for more than 12 seconds (scan cycle is 1 second). Actions taken when the diagnostic trouble code is set: For lost parameters, the module will use default values. Conditions for turning off the malfunction indicator lamp/clearing the diagnostic trouble code.