Switching into Guided from Stabilize with no battery for testing purposes

Hi, I have a Pixhawk on the latest APM software controlling a DJI S1000 octocopter and connected to Mission Planner. I want to test sending MAVLink commands over telemetry to it without spinning motors, aka just removing the battery. It allows me to arm and “take off” without the battery in stabilize mode, but when I try to switch to Guide from Stabilize mode it refuses and gives me a buzzer warning I’ve never heard before (high, low, pause, high, low) then stays in Stabilize mode. Does any one know what this warning could possibly be (sorry for the poor description)? Or does anyone know another way to bypass this warning? Maybe even knowing another way to test?

This would be super helpful to anyone not wanting to waste battery or risk their drone during testing the autopilot.

Guided requires GPS lock

Indeed, I have a GPS signal with 6 satellites and it is a 3D fix. Do I need something else besides this?

If you have a telemetry connection (don’t use the USB cable connection) check the reply that ArduPilot sends on the messages tab on MP