Pixhawk 4 GPS from Holybro doesn't work with Pixhawk 2.4.6

I am trying to connect the Pixhawk 4 GPS from Holybro to my Pixhawk but can’t get it work.
I have connected only these: +5v, RX, TX, SCL, SDA and GND to my Pixhawk, but the GPS unit doesn’t show a sign of being powered up.
Has anyone successfully connected this GPS to Pixhawk?
Do I need to provide the 3v3 also to make it work?