By Jim Piraino. Over the past couple of months, it has come to my attention that auto repair professionals are seeing a rise in the failure rate of the wheel sensors that supply the signal to Tire Pressure Management Systems (TPMS). Most of these failures are due to dead batteries, as each of the four sensors has a non-replaceable battery built into them. In most cases, these batteries have a life expectancy of 5 to 6 years. Although some upscale vehicles, such as BMW, have sophisticated systems that allow the technicians to monitor battery life as a percentage (using a scan tool), most will give no warning of pending failure. For the millions of vehicles rapidly approaching this 5 to 6 year age bracket, it’s not a question of if the sensor will fail, but rather when it will fail.