One of the most common questions I get asked is, what is the life expectancy of the TPMS sensors? Followed by can the battery be replaced? Both are very good questions with sometimes some not so good answers. First question, up to seven years, for the average consumer this is great 7 years is longer then most people retain cars. Second question, No unfortunately not, like an Ipod the sensor has an encased battery that once used up cannot be replaced.
When asked how long the sensor batteries will last, industry representatives provide a broad life expectancy range of five to seven years and up to 100,000 miles are mentioned when addressing estimated life spans. The follow-up qualifier is that driving conditions, such as frequent on-off cycling of a TPMS, tire pressure sampling frequency and temperature extremes, will significantly shorten battery life. Translating to they cannot guarantee a specified amount as many things affect battery sensor life.
Mandated TPMS systems were phased in from starting from 2007, so some of these vehicles sensors have been in service for five years. It is highly likely that many of your factory equipped TPMS sensors are running low on battery life and may expire very soon. Still older direct sensors can be found in quite a few domestic and import models introduced earlier in the decade and equipped with TPMS ahead of government deadlines.
Direct TPMS sensors commonly use radio frequency technology to transmit measured tire pressure readings to a vehicles on-board electronic control unit and warn drivers of a 25% or more under-inflation level. These are mounted inside a tire assembly on valve stems or wheel rims, the sensors are usually powered by 3-volt lithium ion batteries, but some use 1.25-volt nickel metal hydride batteries. There are developments underway that promise battery-less sensors in the future, having the potential to dramatically change TPMS markets.
For now, though, the batteries are generally round and encased in a sensors molded plastic housing have finite lives. Since the batteries are entombed, a dead or dying one requires the replacement of its entire sensor assembly.