Liebherr Biofresh too cold

[fredstone]

I have a two-year-old Liebherr SBNes4805 (Biofresh over freezer) The bioFresh compartment freezes, even on the warmest (b9) setting. Temperature indicated in display shows 3C (much lower than it should be). But no fault codes are shown..

Freezer controls fine. Unit has a PCB control unit common for biofresh and freezer.
Any clues?

[fridge 09]

Yes i would change the bio senser and the fridge senser 1st only about £15 each, before changing board