Tire pressure monitor, which tire is it?

[Docboy]

I had to get one of my tires TPMS sensor replaced yesterday; the "Check your TPMS system" message came up, and the Discount Tire tech said one of the tire's TPMS sensor battery was running low.

He replaced it, message is gone, but now I see this. One of the tires is way overinflated. I believe it is the rear passenger tire, as the valve on this tire looks somewhat different than the other ones. Can anyone confirm before I let out out some air from said tire?

Does anyone know the order of the PSIs? I believe the first top one is the spare tire.

 

[40Man]

On my 11 LC I thought it showed up on the dash screen based on how they are input in techstream or with the programmer. Not sure if the LX570 is different or not.

My 16 senses each location and maps them accordingly.

 

[TimCFJ40]

There's no way of knowing, as they aren't in any order on the screen, and that order changes each time you rotate the tires.
That said, a trick an old trucker showed me was to hit the tires (Not the rim) with an axe handle or similar. The "ping" sound it makes will be duller the lower the pressure. I'd imagine you could find the one that was way over pressure this way, or just by thumb pressure on the tires.

 

[rusty87]

Or just use a tire pressure gauge.

 

[Docboy]

Didn't have time to check with pressure gauge. I'll do it at lunch, thanks. I would think a $80-90k vehicle would have better tire pressure info than the you-go-figure-out-which-one-it-is we have.

 

[Docboy]

I checked all 4 tires with tire pressure gauge, all 4 register mid-high 30psi. That leaves the spare tire. How does one measure spare tire pressure without having to remove the tire?

 

[CharlieS]

You could crank it down so you can access the valve stem without actually removing it. As long as nothing is seized, it is quick and easy to do.

 

[bentonrover]

Just inflate/deflate each tire and right it down

 

[grinchy]

It has to be the spare because otherwise it'd be easy to address. That's just how life works.
You can look at your tirewall, if 55 psi is below the max pressure there isn't any reason to fiddle with it until next time you're rotating, just fix it then.