2007 Prius Tire Pressure Sensors

dhoward

Apparently the tire pressure sensor is integrated with the valve stem. If I buy a set of new tires, sometime in the future, does this mean I must have the tire dealer keep the valve stems for the new tires? I thought that typically they would use new stems.

B Rad

<div class='quotetop'>QUOTE(dhoward @ Apr 23 2007, 12:53 PM) [snapback]428462[/snapback]</div> YES! Just tell who ever you buy new tires from to take the Valve stems/tire sensors out of the old tires and put them in the new ones....Should be no problem and no added cost !!!!

Bill Merchant

Um, the TPMS is mounted on the metal rim, not the rubber tire. You don't need to replace the stems when you replace your tires. Just be sure the people replacing your tires know there is a TPMS and they should be careful of the stems and unit inside the rim. It's a PITA to have one replaced, even if the tire place pays for it. Each pressure sensor must be registered with your car by the dealer.

Welcome to PriusChat, dhoward!

dhoward

<div class='quotetop'>QUOTE(Bill Merchant @ Apr 24 2007, 01:42 AM) [snapback]428877[/snapback]</div>
So you are saying the stem stays put when a tire is removed from the wheel? It does not get removed with the tire?

Charles Suitt

Hi dhoward...

YES... that's exactly what Bill said. The TPMS sensor is attached to the rim, not the tire. The caveats previously posted are dead on right. You need to caution the installers of new tires to be aware of the sensors at the base of the valve stems to avoid damage to them. Replacement is both expensive and requires reprogramming to the Prius computer to operate properly.

If you change rims, as some do, and have the TPMS system, you must be sure the new rims are compatable with the TPMS sensors. I believe it involves the exact configuration of the inner part of the rims at the valve stem hole.

ENJOY your remarkable Prius.

__________________
Charles Suitt
Dallas Texas
2007 Touring Edition
(Former Prius: 2004)

galaxee

non-TPMS valve stems are typically replaced when you change out the tires. just good practice. but with the TPMS, they just leave em in. tell the guys about it in advance so they can be careful when removing the tires.

darrylp

Good to know. Thanks!

Now my problem....Tire pressure on my 2007 leaks down from 40 to 20 every few weeks. It's different on each tire but all tires are leaking.

Anyone else run into this?

whitslack

I was experiencing this with one of the tires on my 2006. It was losing about 3-5 PSI per day, so I was having to refill it every couple of days. I took it to Firestone Complete Auto Care, and they did a patch job on the tire, but it still leaked, and I continued refilling the tire every couple of days.

This past weekend, I took the air compressor hose off the valve after refilling the tire, and air began blasting out of the tire through the valve. My repeated fillings broke the valve, apparently.

I took it in to Gatorland Toyota this morning, told them what had been going on, and they replaced the valve as well as the valve core for free. The invoice says the valve core was defective, so I'm guessing that's why I was losing pressure.

darrylp, maybe you got a bad batch of valve cores.

cyberprius

So, wait. Everytime I have ever bought new tires (all without the monitoring system), I have been told I SHOULD (for what reason I don't know, safety?), get new valve stems.

Was I being cheated before, or are we just taking a chance for cheapness now.

Hey, reading that back, I kind of like that. Chances for cheapness!

David Beale

-Rubber- valve stems do wear out. The rubber rots. The TPMS valve stems are metal. By the time the "O" ring that seals them to the rim wears out you will need to replace the TPMS unit because the battery will be dead. The battery is sealed inside the part of the TPMS unit inside the rim. So far nobody with a 2004 (which presumably will be the first group to have to worry about this) has posted about a dead TPMS unit due to battery failure, so that's a good sign they may last 10 years or so.

Note that -all- currently commonly used valve stems mount in the rim. Inside the valve stem there is a valve core that can be replaced if you want. Just make sure the replacement is the same length as the original (there are several lengths, which may or may not be compatible).

If you do start having trouble loosing tire pressure, check inside the valve cap. A common trick kids used to do was lodge a small pebble inside the valve cap. It pressed the core down releasing the seal, and air slowly escapes past the valve cap. Don't ask how I know about this.

__________________
Edmonton Alberta
"Pearl" is a 2007 Driftwood Pearl Prius.