Battery Voltage not transmitted to Pixhawk 2.1 "Cube Orange"

I am using a Pixhawk 2.1 “Cube Orange” in conjunction with the PDB-BEC-PL-4-14-HYB

The connection is shown in the following figure:

The Pixhawk doesn’t get the info about the battery voltage. What is the reason? Do I need an additional cable?

Thanks for your help!

Dear @Sven.Schmid,

from my perspective you are needing a PL-Sensorboard like: MAUCH PL Sensor Board inkl. CFK Gehäuse | MYBOTSHOP.DE, 41,95 € because the MAUCH 022 is just a BEC.

Yes, this might be the explanation. Thanks a lot!