That info should be on the drivers door jamb.
Check the label on the drivers door jamb. That has the recommended pressure.
Tire Pressure Monitor System
You either have a failed or a missing tire pressure sensor.
Tire pressure is 33psi, give or take 2 lbs. Always go by the manufacturer's recommendations for the vehicle, NOT the maximum tire pressure on the tire.
The tire will have the pressure on the sidewall. I have seen 44psi there, but, that feels a little hard to me. I have kept them at 40psi and been just fine. The pressure listed on the side of the tire is the max safe pressure for that tire. The recommended pressure for a Jeep Liberty is on the label affixed to the driver's door jamb. It is more in the 30-35 psi range.
2,4bar both fully loaded and when not.
you motor oil is low
There are two tire sizes for the 2005 liberty depending on the installed wheels.235/70-16 and 225/75-16
Look at the plate located inside the drivers door.
I believe that it means your tire pressure is low.
It is under the rear seat on the passenger side. Tire iron and jack are secured underneath with a large handscrew.