Kawasaki says the TPS batteries should last approximately 5 years. A lot of them seem to be failing long before that age though. The TPS sensors have been changed twice but they <seem> to be using the same technology and battery as the first units. Perhaps the low voltage warning has been set a bit lower and these new sensors will go longer before generating the warning.
Brian
I have "low TPS sensor battery" message flashing now for both sensors when I first ride the bike. At first it was only he rear one. The bike is an '09 with low miles.
For the asking price these clowns have for these sensors, the batteries should last at least 50 years, not 5.