TPMS Sensors.

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I mean it’s magic right? It’s gotta be magic. How would they even be powered? Or connected to anything? You’re telling me they just sit inside a tire and know shit and communicate it?

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The motion of the wheel charges the sensors, similarly to a self-charging or self-winding wrist watch. They then send a signal back to the vehicle using RF

You ever have one of those flashlights that you shake back and forth to charge it and it lights for a couple minutes and then you have to shake it again? TPMS sensors work kinda like that. That movement of the tire helps them to charge. They talk to the car’s computer using a small, low-power radio.

Dunno why people think that TPMS sensors charge themselves.

They just use a battery. It lasts up to 10 years but when it dies you just swap out the whole unit usually. They don’t need to communicate often so they just sleep in a super low power mode most of the time and only take a reading occasionally.

I’m a used car dealer, and it’s something I often have to service on cars.

Inside the sensor you have a battery like those found in watches:

[https://res.utmel.com/Images/Article/91c38b71-e642-4b16-bd82-e49d04df1259.png](https://res.utmel.com/Images/Article/91c38b71-e642-4b16-bd82-e49d04df1259.png)

They die after a few years, and have to be replaced. This is often serviced when people buy new tires every few years.

The TPMS sensors have a tire pressure sensor. The sensor has a battery that will run out every few years. The car receives a signal that one of the tires is low — they often have to be pretty low for some sensors to catch it — and the system in the car displays the warning.