Bought this TPMS about a year and a half ago. Was working fine until the LF display went blank last week. The display's initial power-on self-test works fine. I thought maybe the LF sensor battery was dead. Measured 2.8 volts with a new battery removed but replaced (3.2 volts). Had then (before driving) still the same result. I suspect that the low frequency sensor is defective. Just drove and now the LF data is back. Expect other wheel sensor batteries to be replaced soon. Don't remind yourself of beeps or other signs of low battery.