TPMS ( Tire Pressure Monitor System ) Problem

[galaxee]

disable tpms? if only. speculation is that you can do it by unplugging the ecu, but it ties into so many other things that who knows what would happen. you could be the first! it's right next to the ps ecu. says tpms or something along those lines on it.

[TheForce]

Well if it cant be disabled or tricked into staying off some how I guess I can give unplugging a try. If that don't work I can always disable the idiot light by desoldering a few things and adding a switch in case I need to enable it again. If I have to go that far I would also try to enable the EV light again while I'm back there.

[007Prius]

<div class='quotetop'>QUOTE(galaxee @ Aug 1 2007, 07:55 PM) [snapback]488968[/snapback]</div>

disable tpms? if only. speculation is that you can do it by unplugging the ecu, but it ties into so many other things that who knows what would happen. you could be the first! it's right next to the ps ecu. says tpms or something along those lines on it.
[/b]

I'm really suprised that someone has not figured out how to disable the TPMS in a Prius, other Toyota's are just a matter of grounding the TPMS LED wire, is the Prius much different?

[TheForce]

OK I'm back from my dealer and I still don't know whats causing my problem.

First I had to fix their Techstream computer because someone flipped the screen resolution so the screen was in the vertical position instead of the regular horizontal and no one knew how to flip it back. This is a simple proble for me to fix because it happens every once in a while where I work.

Next we tried reading the transmitters in the tires. We was able to read all of them just fine. I was amazed with the program they used. It read the PSI with in .1psi. Its pretty cool. It also had the pressures that tripped the TPMS light. Everything there said it would trip when pressure dropped %20 from my current pressure.

Then I tried turning on my PC with both bluetooth and wifi enabled. The Techstream computer was still able to read all the pressures in real time.

So now I'm left with WTF. We went over a few ideas and one of the things I'm going to try is lowering my tire pressure back down to the low 40s to high 30s for a while. Another idea is that maybe going over bumps in the road might cause it to trip the TPMS.

I will continue to diagnose the issue and post results when and if I get them.


I really want a Techstream or heck even the ScanTool. <_< Will someone buy me one?

[FL_Prius_Driver]

<div class='quotetop'>QUOTE(TheForce @ Jul 19 2007, 10:19 PM) [snapback]481969[/snapback]</div>

Does anyone know what frequency the TPMS emits?

[/b]

This should help. 315 or 433 MHz

http://www.atmel.com/dyn/resources/prod_do...nts/doc4616.pdf

[TheForce]

Well after about 200 miles the light has not come back on. I have not even changed the tire pressure yet. I think I will ride this one out and if I get the light again I will drop the pressure and do some further diagnostics. I guess I just needed to take the car to the dealer and scare it a little.

On a side note I really think Toyota should include the tire pressure on the MFD some where. The Techstream computer was able to show all 4 plus room for a 5th sensor with psi readings like 40.3psi. What would be interesting is if the Prius can really handle a 5th sensor in the spare tire. I should have asked the tech while I was there.

[TheForce]

Here is a quick update.

I never did drop my pressure down to see if that would fix the problem. I have yet to see the light again. Nothing has changed since I took it into the dealer.

[TheForce]

Here is a quick update.

I never did drop my pressure down to see if that would fix the problem. I have yet to see the light again. Nothing has changed since I took it into the dealer.

[mikemartyo]

I am getting a set of snow tires for my prius (08) and i am saving the $345 and not getting the TPMS installed.

Personally i am going to put black electrical tape over the light in my dash
Mike



I just found this link that may help you - on the corvette forum -

now i know they are corvette guys, but they have a novel solution.

Quote:
Originally Posted by NORTY
Here's a possible solution for you to run any tires at any pressure on any rims you want.

Remove the 4 TPMS and get yourself a piece of PVC pipe and thread a schrader valve in one end and a cap on the other. Throw the sensors inside and pump it up to 30-38PSI. Throw the pipe bomb into the back of the car somewhere and you should be able to drive your car without limits on performance. Now, you might need an attorney if you get pulled over with a "suspicious device" in your car but hey, that's what it takes to drive your car nowadays!

Believe it or not, that is a suggestion the GM/Corvette folks at the Birthday Bash suggested also - PVC pipe with 4 spare sensors installed stashed in the back. You'll still need a 'training' tool each time you use the pipe to train the sensors for your car. The GM guy said to screw the sensors into the pipe and use one of them to pressurize the pipe. Makes it easier to train them also.

When through racing, install the street tires/wheels, retrain the sensors (take out the pipe) and press on.

[walterm]

Originally Posted by mikemartyo

I am getting a set of snow tires for my prius (08) and i am saving the $345 and not getting the TPMS installed.

Personally i am going to put black electrical tape over the light in my dash
Mike

Depending on where you store your non-snow tires you may not need to - I have a set of non-TPMS wheels/snow tires, but I think because the car is close enough to where the TPMS wheels are stored it 'reads' them when I'm parked in the driveway.

the only time I ever see the tire pressure warning light is if I drive continously for more than an hour or so, then the lack of signal must cause the TPMS to flag 'something is wrong'. But my normal commute is ~35 minutes, so it doesn't light up on my ride to or from work.