Computer display "LU" at switch on?

[Samozzy]

When I first switch on my cycle computer it displays 'LU' for a couple of seconds before showing the normal display.
I have contacted the bike manufacturer but they don't know what it is telling me.
Can anyone help me? the bike seems to work ok but I'm wondering whether its an error code and I should be concerned about it - I don't want the bike giving up on me miles from home!
Thanks in advance.

 

[trex]

that means 'low voltage'. The LCD has a small battery. Open the rear compartment and replace the silver battery.