TPWS did not work!!!

The TPMS is completely cuddled up inside the rim, I think? I doubt it's touched anything, and the tire was flat for some time.

 

do not know Mendel what is going on, except that the two cases have been relatively severe flats so something could have damaged the TPMS.

I have played with my TPMS enough to know the data registers hold the current data, and if no new pressure data is forthcoming from the TPMS, it holds the old value for some time before setting off the warning light: It is more prompt (minute or two) if the car actually "sees" a zero reading transmitted from the TPMS.

I actually have a TPMS in my glove box transmitting a fake reading to keep the light off. In other words, I have one tire with a bad TPMS.

 

I think wjtracy is on the right path here. As someone who uses snow tires with no TPMS, I notice that it takes the Prius 20 minutes to register the lack of a TPMS signal. As soon as I leave my garage (where my regular tires with TPMS are stored), the car loses the TPMS signal immediately; however, it isn't until 20 minutes later that the light comes on. Seems like the TPMS is designed to warn of gradual loss, not sudden failure.

 

My scenario is the same, ie: snowtires sans tpms, OEM's (with tpms) stack a couple of feet from car in garage. I'll have to pay more attention.

If it's true, that tpms won't warn you if you have a sudden flat, that's about as useful as an ashtray on a motor bike *.

* Just one of the gems I picked up from watching Scott and Bailey.

 

Yes and the corollary to that approx. 20-minute is, if your trips are all shorter than 20-mins, which is our current situation, you can go weeks without the system realizing there is a bad TPMS unit. Note however, this long reaction does not apply to a true zero pressure reading...a true low P reading from a properly operating TPMS will more rapidly set the warning light off. But if the TPMS is broken or not transmitting, then you're back to the slow 20-minutes the system takes to realize a TPMS is dead.