EFI Diagnostic tool becomes inoperable after starting the engine.
The tool will connect just fine and work good up until you start the engine, once started the dashboard gauges go down and the tool is completely inoperable after a few seconds. After shutting the engine down and disconnecting, the tool does the same thing.
Be sure the Diagnostic tool is updated to the latest firmware and software. You can download the latest software on The Power Portal Diagnostic Tool Software Page.
Outdated firmware will cause this issue. After updating the software, it will automatically prompt you to update the firmware.