Let us know what makes them tick. I’m imagining a piston that moves in a bore against spring pressure, and some sort of sensor which detects the position of the piston, and rf transmit circuity to send the info to the tire pressure monitoring computer. It might also be sort of beam positioned in a way it gets bent by the pressure, and whose deflection is measured using a strain gauge variable resistance technique.
I do not know the differece in the metal versus the rubber, but it is always the question asked. I always suspected that the two were incompatible with the system used but the car. Do the tpms readings still show up? That would be my only question. I always asked about changing all the sensors when getting tires but was told to just wait. Some last over ten years. I’ve replaced two out of four now on the one car and none on the other. It costs about $80 after the fact so I guess the extra expense is about $20 a tire. Still nice to have it all done.
Tire pressure sensors have a basic electronic pressure sensor like a Manifold Absolute Pressure sensor.
A little disappointing going to all that work taking it apart and all it is is a battery and mystery circuit board.
I’m presuming the round shiny metal circle is just the battery, spot welded to insure a good connection to the pc board. (If flashlight batteries were connected like this you wouldn’t have to shake the flashlight to get it to work. What a concept!! … lol) It isn’t clear by looking at the photo where the pressure sensor action is located, perhaps it is inside what appears to be the sensor’s valve-stem sticking out to the right.
Ok here is the result!
And that is as deep as I go !!
You can see the corrosion on the INSIDE washer!
Glad it is all done.
FYI on my MM on 9v battery test it read 2.96V
That chip might look like this on the inside.
https://www.avnet.com/wps/portal/abacus/solutions/technologies/sensors/pressure-sensors/core-technologies/mems/