TPMS sensor parts

TPMS sensors are comprised of the sensor itself along with many other small parts. These small parts include the valve stem, valve core, valve cap, nut, washer, and seal. Of course, these components do not last forever, so proper maintenance and replacement is required to keep the entire TPMS system operating at peak efficiency.

When do TPMS sensors and it’s parts need to be replaced? 

TPMS sensors only need to be replaced if damaged or if the battery is worn out, and the durable VDO metal valve stem is also reusable unless it is damaged. Every time you perform tire service on a TPMS equipped wheel, the TPMS sensor service kit parts, such as the nut, washer, seal, valve core, and cap must be replaced, because these parts are designed for one-time use only. 

Why is this required?

In the past, all of these pieces would be reused during tire or TPMS sensor service. This led to many problems, one of the biggest being corrosion of the metal parts. Many factors caused this corrosion, such as the natural elements that accumulated on the sensor, road salt, and bimetallic reaction with the wheel itself. If the valve stem is compromised for any reason, then it is likely that the TPMS sensor is also compromised. If the corroded valve stem compromises the sensor, it can cause problems with your tires as well as your TPMS system, including air leakage and incorrect air pressure or temperature readings. Additionally, replacing all of the service parts ensures a proper sealing of the TPMS sensor on the wheel.

A step in the right direction

More than 70,000 accidents a year are caused by improper tire inflation. By taking the right preemptive steps, drivers and mechanics can help bring this number down. This starts with the TPMS system, both maintaining and evolving it. 

When you get new tires, if your old TPMS sensors are still working, they can be reused. You should however plan on replacing the TPMS sensor service parts. These can include the valve stem, valve core, and stem nut and grommet (on metal stem sensors). These parts degrade over time and can cause the TPMS sensor to fail if not maintained. 

Corrosion at the base of the valve stem, using certain types of aerosol tire inflator or sealer, and exposure to moisture or road salt are some of the reasons why TPMS sensors might fail prematurely. 

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