Check OBD cable seats, module fuses, and termination resistance across the CAN bus lines. Emergency Recovery Protocol
The manual dedicates 20 pages to J2534 configuration. Most techs plug in their Mongoose or VCM II cable and get a "Handshake Failed" error. The manual explains the timing tolerances. Ford modules are notoriously sensitive to latency. If your PC’s USB power saving is on, the FDET will drop the session mid-flash. The manual tells you exactly how to disable that at the registry level. Ford Diagnostic Engineering Tool Manual