2002 TrailBlazer. Vehicle communications with no BCM

GM SI appears to declare the unless the BCM issues a wake up message that other modules in the vehicle may not communicate. This video demonstrates that other modules do indeed communicate without a BCM present on the network. For sure, the engine cannot be started or otherwise operated but you can troubleshoot other modules on the network even without a functional BCM. First seen is a Tech 2 displaying engine data, Transmission data, ATC data, and EBCM data. Next the Torque app connects and displays various engine data. Finally, in Torque I command the fuel pump and then the front axle disconnect to breifly operate which you will hear. All of this happens through J1850 communication with various modules where no BCM is present on the vehicle network.