Good news for many older C14 owners. Searched online and found a Kawi document saying the tpms batteries "are rated for 5 years." I just called and varified this with a Kawi customer service rep and he said, "Take your '08 C14 to a dealer and if he says no (one had already said no), tell him to call us and we'll straighten him out." So, if you need tires, it's a good time to get free installation on those too, since they must be removed in order to install new tpms'.
Kawi document: K-TECH NEWS, vol. 20, issue 2 2007, pg. 12, para. 2.
Google "K-TECH NEWS, vol. 20, issue 2 2007" and it will be the top of the page link to a PDF Adobe document. For those computer challenged an easy link is attached. Lew