TPMS psi treshold

Again, just going to US TechInfo site and downloading the 2006 Owner's Manual, I found this on page 155:



One other thing, doing my own tire rotations (in conjunction snow tire swaps), I gave up on the front/rear pressure differential suggested by Toyota, just set them all the same, a few pounds over spec. Less hassle.

 

hmm well I fiddle around with it next Techstream session.

 

Pearl is a 2007 Prius, has the reset button, and it works.

Pearl S is a 2012 Prius, has the reset button, and it works.

As per the owners manual in both cars. RTFM!

There is a lot of mis-information being propagated here. Please read my previous post.

 

Techstream will read the exact tire pressure.

Techstream also lets you register new sensors, but you must know the sensor's ID number, which is printed on the sensor. So if you put a new sensor on and mount the tire, you're out of luck.

 

Thank you...I am wondering if alarm set point is shown in Techstream. I check next time. Seem to recall a 26 psig setting in there.

 

On my Gen 3, Techstream does show the set point, as well as the current pressure, and the current temperature.

Whether it shows the same info for Gen 2, I don't know.

-Chap

 

For benefit of future readers, that was just an explanation of why to reset the TPMS after a rotation. Because it does only associate pressures with serial numbers, and doesn't know what corners those are at, it will have the wrong alarm points after a rotation if it is not reset.

Sure, nobody says you have to care about resetting after rotation, but that's a different question than how the system works.

It seems to me that the default alarm points (if you reset at your desired pressure) are lower than I would like. When I owned a Gen 1 (which uses smaller tires), I once went through the load-capacity-versus-pressure tables and found that, while they were adequate at Toyota's published pressure, there wasn't much margin for error; you really wouldn't want them getting, say, 6 psi low, especially in front.

With the later generations using bigger tires (but also being heavier cars), I have not had another evening in the library to repeat the same exercise ... I just continue assuming the spec'd tires might not have a large capacity margin, so to me it makes sense to do the overinflate-reset TPMS-deflate-to-desired-pressure trick, so I can count on getting warned early when the pressure is low. And if you're trying to set an alarm threshold within a couple PSI of your desired pressure, then the front/rear difference will be worth taking into account.

-Chap

 

Considering the (reputed) 25% drop in pressure needed to trigger the warning, the couple of pounds difference between front and rear tires is trivial. I figure the difference is so trivial I ignore it, just set all the tires to the same pressure, slightly higher than spec. TPMS aside, this makes tire rotation simpler.

 

I am afraid Chap caught me red-handed on that...I am not a reliable tire rotator.

 

They rotate every time you move the car.

 

Yes, I can see current sensor pressure, current sensor temperature, set pressure point and alarm pressure point for each tire (2009 Gen II)