TPMS Question

The answer is 'both'.

There are pressure sensors in each wheel, combined with the inflation nozzle. Each sensor has a specific ID number and a small battery to power the transmitter.

The car has a receiver that can be programmed to read 4 individual sensor IDs, and remember a setpoint for each. If the pressure drops below 75% (I think) of the setpoint the dash light goes on.

 

The sensors are part of the valve stem and are inside of the tire. There is a TPMS reset button in the car about where your right knee rests so you can reset the TPMS alarm point if you change tire pressure significantly. You need to be careful removing and installing new tires as you can damage the sensors.

 

Here's another TPMS question. I have a 2012 Prius C 2 which did not come with TPMS sensors in the wheels. At least I'm pretty sure I read it didn't come with TPMS sensors. Looking at the tire valves they look like plain old fashioned non-sensor valve stems to me. I was relieved not to have sensors to falsely set warnings since I'm pretty good above manually checking tire pressure anyway.

So why the question? Last month I bought snow tires and rims for the car. About a week after they were installed the TPMS warning light started flashing. I reset it and about a week later it came on again. Rince and repeat. I didn't pay for valves with sensors for the new rims so I'm pretty sure I still have just plain valves. Is there something the tire place might set that activated the TMPS? Can I turn it off or do I just have to continue ignoring the warning light?

On another topic, it has been a pretty big snow year and the C has been great in the snow and ice with the snow tires.

 

Your TPMS is working as intended. Since your new rims do not have sensors the only thing to do is ignore the warning light or cover it with black tape.

 

Your car came with TPMS sensors.

Turning it off is not an option.

 

Check in your owner's manual to see if you have the pressure sensors or if the car senses the rotation of the tires for the monitoring system. It may be different in Canada.

 

Thanks for the responses. Bummer about having the sensors. I did just go out and took a look at my summer rims and sure enough they have TPMS valves. I don't know how I missed that before but I guess the part of the valve that sticks through the hub cap looks like a regular valve. Guess the light will go off when the summer rims are put back on in the spring. I can live with that.

 

Yep, some sensors have metal valve stems, some have the rubber ones.

 

At least the light is not always on. Comes and goes, at least it did for me. I covered my light, I thought it was annoying while driving at night. I like to turn down the intensity of the dash down at night. The idiot lights will not dim.