I have a 2014 1200GS, the bike sat for a year fro the most part due to OCONUS location of myself. When i got back, the rear tire sensor would show the pressure, then a line would be in place of the PSI, the 911 does not show low battery. At times i get the exclamation point for the rear pressure sensor. while riding i can watch the sensor work and not work. I still do not have a fix, out of warranty, not paying BMW to troubleshoot. Any suggestions?