GR64 power on status pin problem


I have problem on checking a pin vref. I want to detect Gr64 power on or off.

I use pin vref to check voltage. I power on module. Led is light on. I measure pin vref. It have Voltage. work.

I put 3.6 V to pin DFM1 to simulate connected to MCU. I measure pin vref. It have Voltage as same as power on.
So I can’t check pin vref when I connect it with mcu. I try many module it the same.

How to detect module is power on/off? Power on /off is the same pin.
I try R4A and R4B. I can’t use R5. some function has problem with my application.