Most TPMS failures are caused by tire pressure sensors that have reached the end of the road. The batteries inside the tire pressure sensors have a service life that typically ranges from 5 to 7 years. The service life can vary depending on how many miles a vehicle is driven (the more it is driven, the more frequently the sensors generate a signal and drain their batteries). Tire pressure sensors also can fail as a result of corrosion on or inside the valve stem. This has been a serious problem with some makes (notably Toyota) and has resulted in valve stems cracking or breaking off and making a tire to suddenly go flat (just the sort of thing TPMS sensors were supposed to prevent!).
Corrosion is an issue with sensors that have aluminum stems, not the ones with rubber stems. TPMS module, keyless entry and wiring faults can also prevent a TPMS system from working, but these types of problems are much less common. When a tire pressure sensor fails, the TPMS system should detect the fault and turn on the TPMS warning light or cause the light to flash.
Unfortunately, many motorists don’t know what the TPMS warning light looks like or what it means, so the light may be ignored. The vehicle is still safe to drive as long as the tires are holding normal air pressure, but with the TPMS system offline there will be no low tire pressure warning if a tire starts to go flat.
Generally, TPMS sensors should be replaced when needs it first set of tires, or after 5 to 7 years or 60,000 to 80,000 miles. The TPMS sensors may still be functioning when the first set of tires are replaced, but chances are they won’t have enough service life remaining in the batteries to last a second set of tires under normal driving conditions. TPMS sensors come in various styles and designs, and some original equipment sensors can be very expensive. Most aftermarket sensor suppliers now offer some type of “universal” replacement sensor that can be programmed to work in a wide variety of applications. The electronics in these sensors have numerous protocols so they can work in various applications. Some sensors transmit at a frequency of 125 KHz while others transmit at 309 MHz, 433 MHz or other frequencies. A universal sensor reduces your inventory requirements and makes installation easier for your professional installer customers — although they will need a TPMS service tool to program the sensors for the application and to reset the system.
Do replacement TPMS sensors have to be the same type as the original?
No. As long as the sensor generates the same signal frequency and broadcast the same information as the original, the actual design of the sensor should not matter. Direct replacement TPMS sensors are identical to the original (same fit and function) while universal TPMS sensors may differ from the original design. Large TPMS sensors that are mounted in the drop center of some wheels with a steel band can be replaced with a snap-in style rubber valve stem sensor.