Any safe way of knowing if it's broken?
yes, fix the tire and see if it resets. I don't replace much of anything that isn't broken. You can buy the canister of goo for the mobility kit for about $40? or just get a can of fix a flat and top off the low tire with the compressor...
2002 BMW M3 6spd
2009 BMW 650 coupe (lease up)
2013 BMW M3 IB