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While reading the manual on my new '06 Prius, I noticed that it comes with a "direct tire pressure monitoring system" which appears to be standard equipment on the car. Anyone got a simple version of how it works. From the manual, it appears that each wheel has a sensor and transmitter that relays info to the monitor. If a tire is low, a light comes on in the dashboard warning area.

Because of this system, it appears that Toyota is recommending that ANY tire replacement be done by a Toyota dealer. Normally, on my other cars I have all my tire work done at Costco or Les Schwab. I'm not too excited about having to visit my Toyota dealer for tire problems although having this system on my car certainly can be VERY beneficial in spotting a slow leak early enough to correct before it goes flat.

Perhaps this system was on the '05, but I certainly never heard about it during the '05 run or from anywhere else about it being standard on the '06. For anyone who has the '06 and the manual, the system is described starting on page 150.
 

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ElectronMotion said:
While reading the manual on my new '06 Prius, I noticed that it comes with a "direct tire pressure monitoring system" which appears to be standard equipment on the car. Anyone got a simple version of how it works. From the manual, it appears that each wheel has a sensor and transmitter that relays info to the monitor. If a tire is low, a light comes on in the dashboard warning area.

Because of this system, it appears that Toyota is recommending that ANY tire replacement be done by a Toyota dealer. Normally, on my other cars I have all my tire work done at Costco or Les Schwab. I'm not too excited about having to visit my Toyota dealer for tire problems although having this system on my car certainly can be VERY beneficial in spotting a slow leak early enough to correct before it goes flat.

Perhaps this system was on the '05, but I certainly never heard about it during the '05 run or from anywhere else about it being standard on the '06. For anyone who has the '06 and the manual, the system is described starting on page 150.
Hello ElectronMotion, Yes the Tire ( Low pressure ) monitoring system is new to 06 Prius but have been around on other Toyotas for a few years already. Toyota started the system on the 04 4Runners off road vehicles 1st if I recall it right. The 5 tires including the spare ( SUV's ) has a valve steam that uses radio signal emitted to the main CPU that monitors the 5 tires pressure again, on the SUVs. The 06 Prius has the newer system but only works on the 4 tires on the ground the spare tire is not monitored. I have been told ? I believe that you do not have to take it to Toyota for tire replacement as long as the radio signal emitting valve stems are working properly.
 

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Yes, if I had to choose one tire to monitor, the spare would be it!

Why is that? Do you have lots of broken glass and rusty nails in your trunk? Otherwise, I'd say the spare tire in the trunk is pretty reliable to cover the short distances it's designed to in case of a flat, and doesn'e need monitoring. Which is probably why Toyota cut that waste cost.
 

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I'll notice a flat on one of the four mounted tires, but the spare, under all that stuff in the back, doesn't get checked as often as I should. All tires lose pressure slowly, and at 60psi, the mini-spare can lost it faster than most. With the spare monitored, I'd know that before I am on the side of the road with a flat spare and out of cellphone range.
 

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KTPhil said:
I'll notice a flat on one of the four mounted tires, but the spare, under all that stuff in the back, doesn't get checked as often as I should. All tires lose pressure slowly, and at 60psi, the mini-spare can lost it faster than most. With the spare monitored, I'd know that before I am on the side of the road with a flat spare and out of cellphone range.
KTphil, carry a gas pressurized air canister, I have one in the tire compartment of my 97 Supra. The tire ( Spare ) is Flat all the time!
 

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C.Rickey Hirose said:
Yes the Tire ( Low pressure ) monitoring system is new to 06 Prius but have been around on other Toyotas for a few years already..... I believe that you do not have to take it to Toyota for tire replacement as long as the radio signal emitting valve stems are working properly.
If I get a set of winter wheels and tires and for my Prius, am I correct in assuming that I also would have to get a set of the radio signal emitting valve stems to avoid getting a false reading from the pressure monitoring system?
 

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Yes, if you get winter wheels you will get a tire pressure light. Unless you purchase valve stem transmitters for them from your Toyota dealer.

These systems are funny. For example, on the Mazda RX-8 they are set very sensitive, and owners were complaining about being bothered by the system on cool mornings reporting low tire pressure. By afternoon the tire pressure had risen enough that the warning went out. If you park two vehicles with the system side by side, sometimes they will interfere with each other and give a warning.

You can buy aftermarket tire monitoring systems. They aren't as expensive as the OEM ones. Check out tire shops for prices.
 

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question

Hello,

Does the tire pressure monitoring system give a numerical reading of the pressure in each tire or just a low-pressure warning?

Another way to get at what I'm really asking is...is the monitoring system sufficiently precise and descriptive enough to assist in maintaining optimal fuel efficiency or does it only provide a warning for safety reasons?

Any help appreciated...thanks!
 

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Re: question

aprebyl said:
Hello,

Does the tire pressure monitoring system give a numerical reading of the pressure in each tire or just a low-pressure warning?
It presents a low pressure warning light but does not identify which tire is low.
 

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I read somewhere that if you can tap into one of the computers and get the speed of each wheel you can compare one against the other. If one is running at a different speed then its tyre inflation is incorrect.
 

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orf said:
I read somewhere that if you can tap into one of the computers and get the speed of each wheel you can compare one against the other. If one is running at a different speed then its tyre inflation is incorrect.
Or one tire is worn more than the others.
 

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DanMan32 said:
Or one tire is worn more than the others.
The sensitivity would need to be set so that the speed difference was greater than would be experience by a worn tire.
Also, I seem to think the comprison was done in a strange way because they had 4 lights that blinked when all was well but two came on solid when one tire lost pressure.
Instead of the lights being 2 x 2 (side by side), they were in a diamond shape, the top light representing the front wheels and the side lights representing the left or right side wheels. The bottom light represented the rear wheels.
I did not understand their logic but it had something to do with catering for a turning vehicle where the inside wheels rotate slower that the outside wheels. Apparently the front wheels rotate slightly faster than the rear because they are the drive wheels.
Unfortunately I can't find the article otherwise I would direct you to it.
I thought it was quite neat.
 

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It is true, when turning the wheels on the inside of the turn rotate slower than the ones on the outside. That's why the need for a differential.
 

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Logically, when turning the top and bottom lights would be on.
To indicate a deflated tire only one would be on as well as either the left or right.
 

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Ah, I get it. Top light is comparison between two front tires, bottom light comparison between rear tires, left light between both left tires, and right light between both right tires. I think that could easily be done on the Prius by getting wheel info from CAN.
 
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