Multiple Modules Not Communicating, Where To Start?

Here we have a 2015 Chevrolet Malibu with a somewhat strange concern. The key is stuck in the ignition and it also will not crank. A Prescan using the Topdon Phoenix Smart show on the Topology there is no communication with several module. How do you approach complex looking communication faults? Amazon Store Goodies https://www.amazon.com/shop/automotivediagnosticsprogramming Topdon Phoenix Smart https://www.topdon.us/discount/ADP10?redirect=%2Fproducts%2Fphoenix-smart Favorite Test Light Search J-35616-210 https://gmtoolsandequipment.com/en-US/Pages/ItemDetail.aspx?SKU=J-35616-210 #topdon #diagnostics #Picoscope #autorepair