Tire Pressure Sensors

Hah!.. good guess.... none of the above....

The car knows that each tire has 855 revolutions per miles and monitors it perfectly.. this also plays into the Nav etc when you lose gps signal....as well as determining your speed etc.

At any rate.. if one tire gets low on air, in essence the tire is smaller in diameter and will take more revs compared to the other tires to go one mile.

Thats why when you change the air pressures to where you want them, you will need to hit the reset button underneath the steering wheel to reset the computer.

You will see that button noted in your pocket manual.

This car is alot smarter than you think.... from auto turning off recirc if it smells a bad smell or excessive dirt is in the air, to knowing the humidity of the air and inside and outside air temp as it decides whether to blow cold or hot air on your windshield when you hit defrost.

Thats only the beginning of its smarts!.. the more you learn about this car, the more you will be blown away at how different and so much more thought and TLC went into building it than most other cars.

 

eek. instead of editing this post, i'm gonna start a new topic. DH learned lots in his class down in jax last week. i'm gonna hve to go through and explain it all.

sigh...

 

Sorry windstrings, but you are incorrect here. There are sensors built into the valves. Some cars use the indirect method of measuring "tire pressure" but the Prius isn't one.

There are most definitely sensors in each wheel, and the car has a receiver that compares the values. Whe one drops, the light comes on. And yes, they are over $100 each.

 

See my thread in Care, Maintenance and Troubleshooting. [edit: here's the link] http://priuschat.com/index.php?showtopic=15228&hl=

There are indeed valve stem sensors AND the indirect system.

DocVijay AND Windstrings are both correct to some degree.

 

The 2006 has the direct reading system... the pressure sensors are located in each valve stem. $106/sensor according to my dealer.

/Jim (not looking forward to have to buy 8 more)

 

it has both direct and indirect. check out the thread i linked to. there i explain that the RESET button indicates that the indirect system is also present in the car and why the reset button doesn't apply to the direct sensors.

 

actually, technically the valve stem is a part of the presure sensor... but i guess that can go the other way too

 

Galaxee,

Do you know how many tire pressure sensors can be registered into the ECU? I sure hope that it is at least 8.

What is the recommended proceedure for having 2 sets of wheels (summer and winter)?

Thanks for the info about the direct... and indirect monitor system.

/Jim

 

this info isn't exactly in the book. but here's what it says.

and not relevant, but of interest

from that third bullet point, it sounds like you'll have to re-register everything in the spring and fall. i have no idea how much this would cost at the dealer, and DH is sleeping off a migraine so i can't ask him right now. i'll see what i can get out of him later.

 

Thanks Galaxee. I will look for a follow-up soon. I sure don't want to go to the dealer to set the codes. Is this a toyota specific device... or is it common enough so that normal tire shops (or mechanics) would have one?

/Jim

 

I wish it worked the other way around!! I was driving through Avondale this evening (mushroom capitol of the United States and, thusly, smells like manure for the 5 mile drive through town. I had to manually go in and turn on recirculation. Phew!

 

okay. first. do you have a "main/2nd" button in your glovebox? or anywhere else in the car? this will let you switch between 2 sets of tires so once your 2 sets are registered you can just toss on the appropriate set of wheels and hit that switch. let's hope they had the presence of mind to install that switch!

if you don't have that button, this starts to really suck. you'll need to have the sensor codes written down (a 7 digit number listed on the actual sensor) for each set. not so bad for the new sensors because this can be recorded before installing them into the new wheels... but this means at some point pulling the tires off the oem wheels and noting the numbers on the original set of sensors and then reinstalling the tires back on the rims. then, you'll have to have the dealership clear the numbers from the ECU for the first set and re-enter the numbers for the new set when you want to change the wheels. DH said this will vary from dealer to dealer, but they may charge 0.5-1 hour at whatever their labor rate is. just to give you an idea, the rate at his workplace is 71.99/hr. i don't know if non-toyota places have the toyota scan tool. maybe a toyota specialist shop- call and ask if they have the THHT first before scheduling an appointment.

so like i said, hopefully toyota put that main/2nd button on there. life would be really easy for all you guys with 2 sets of wheels if that were the case.

 

i should post this here too.

i have found a major conflict between a handout from this class and a book chapter in the materials. i am having DH consult a third source at work before confirming anything about the dual-TPM systems. sorry to cause any kind of shake-up, guys... i am a perfectionist so i guarantee i will set this straight. i also hate to break my reputation for being helpful and informative by possibly spreading info that might not be right. sigh...

however, the info for each of the systems is correct. the question is whether the dual systems really do exist on the 06 prius.

 

Galaxee, I don't think there is a second button to reset a second set of sensors. I just bought my '06 and wanted my snow tires and rims from my '05 mounted on my '06. The dealer said fine, no problem. Well, it was a problem. The tech said I couldn't use my snow tires on the OEM rims(2nd set) they were mounted to because they didn't have the sensors. I had to have the snow tires mounted on the '06 rims. If there was a reset for a second set of sensors, I could have just purchased 4 new sensors for my snow tire rims. The dealer told me I would have to have the numbers scanned in everytime I changed rims and it would cost $90 bucks. By just changing out the tires and using the same rims it would only cost me $60 bucks each time and I wouldn't have to cough up over $400 for four new sensors. I just hate this because either way I have to go to the dealership to change into snow tires instead of doing it in my garage. This was a big todo because changing over to my snow tires was a condition of the sale and no one on the sales side knew anything about this.

Please let me know if I was told a bunch of junk or if it's the truth.

 

i don't have an 06... i am relying on someone who has one to tell me whether the button is in fact there. did you check your glove box to see if the button is there? if it isn't, the whole situation really does suck.

 

My tire dealer charges $50 to mount and balance 4 tires if they are not on rims. Alternately... they only charge $0 to change tires (incl balance) if they are already mounted on rims. If I have to pay Toyota $35-$70 just to re-program the ECU twice a year... I might as well not mount the winter tires on rims.

Actually... my tire dealer said that he technically does not need to remount the tires when moving the TPM from rim to rim... He said they can push it into place while the tire is already on the rim. Maybe I will not buy the 8 additional TPM senders and save the $848 (8 X $106)... and then let the tire dealer move the TPMS from rim to rim each year on each of our two Prii.

After I get the rest of the data from Galaxee on Tuesday or so... I will talk to my tire guy.

/Jim