it seems after the update to Lollipop and Marshmallow the code has Changed to enable Hidden Menu and so here is the new Code
The Code is *#546368#*MODELNUMBER#
My model Number on the phone im working with was LGUS991 that is Displayed on the hardware INFO screen in about Phone . USE ONLY THE NUMERIC NUMBER
Your Model may be different .
Once you enter the correct code +model Number go to
Port Check Test
You now have DIAG MODE ENABLED and CDMA will read the Com Port assigned to the phone .
If this Information was Helpful please thank me.:cool: