BMW lifetime digital tire pressure gauge

I have one of those "lifetime" guages that reads in PSI to a 0.5 PSI
accuracy. The beeper sound was weak, then today it showed an "L"
instead of a pressure reading, so I removed the CR2032 battery, and
put a new one in a few hours later.
Now it shows "01.0" when I read something that is at least 30 PSI, and
does not beep.

Does the unit need calibrating, or pitched away? Will BMW honor any
sort of lifetime warranty? TIA
.