[UPDATE] I'm not sure about the battery but after a few months they start to fail intermittently. I have to reset the TPMS in iDrive about once a week. the change to 2 stars works fine on my 2009 335i e93 pre-lci. Make sure you use the app sheet on the manufacturer's website to ensure it works for your vehicle. Installation took a few minutes, a few more minutes the machine registered new sensors, and now the TPMS indicators are gone!