TPMS Interesting Observation

[charlier180]

I realize the TPMS has been discussed extensively but I still thought my experience was interesting enough to pass on.

About a week or so ago I put my snow tires (245/75/16 Blizzaks mounted on steel wheels) on my 4Runner. These wheels do not have Tire Pressure Monitor sensors in them. This past Saturday I was about 120 miles into a trip and the TPMS indicator starting flashing on the dash. On Sunday we pulled my 4Runner into my friend's shop and checked all tires including the spare. We made sure the pressure in all the tires (including the spare)was 36 psi. BTW, the spare was 32 psi and the tire and valve stem were not dirty. I left the 4Runner in his shop (60 degrees) overnight. I drove home Monday morning and did errands all day long with the TPMS indicator on the dash flashing.

This morning when I went to work I noticed the TPMS indicator was not flashing. The interesting part of this story is that my 4Runner sat next to my enclosed car trailer all night. Being both lazy and short on garage space all four of my 4Runner's Dunlops with their alloy wheels complete with their TPMS sensors are stored in the trailer.

So what caused the TPMS to stop flashing? Certainly was not the tire pressure in the spare increasing from warming outside temps (temp went from 38 degrees yesterday afternoon to 9 degrees this morning). The spare tire had it's pressure increased to 36 psi almost a full 48 hours prior to the light going out. Theories anyone?

BTW, prior to this incident the TPMS indicator never came on except for a couple of seconds during startup for the 1 year+ I have owned my 4Runner.

 

[Kmvreter]

I realize the TPMS has been discussed extensively but I still thought my experience was interesting enough to pass on.

Theories anyone?

Happens to me. Wheels are in the basement but are still close enough to send a signal. The stored wheels are sending an OK signal (therefore no lights) when you park near them. The light went on after 1 hour of being away from the signal. Resets every time you turn the truck on and are near the sensors. Test it out by partially deflating one of the stored wheels. The light should come on steady. My seasonal "fix" is a piece of electrical tape over the light during winter.

 

[Bobby]

The sensors emit a constant signal at 315mhz (maybe a little different freq) to a receiver in the truck. When it was close, it probably picked it up. The TPMS light on your dash should've went off as you drove away and the signal was gone.

The light on the dash goes off when pressures are lower than 26psi.