tpms compatibility?

[bwong2]

hello.
i have a multi part tpms question for you guys.

1. i'm looking to get my first set of aftermarket wheels and was wondering what you guys do as far as tpms goes. do you:

a) ride with the dash light on
b) disable/bypass a la ctscott
c) transfer your tpms sensors from your stocks
d) buy new tpms sensors so you can run summer/winter wheels

2. i have a new 2009 liftback yaris. if i were able to acquire a set of 2008 stocks and strip the tpms sensors from there, would they be compatible with a resyncing? also, any idea on how much it'd cost to do it? i hear places like walmart could do it for relatively cheap but is it safe or should i take it to someone who specializes and pay the upcharge?

i'm looking at running my aftermarkets during the summer and putting my stocks on in the winter. any input/recommendations would be greatly appreciated. great community and great wealth of information here guys.

thanks!

Brian.

[CTScott]

I now have three sets of wheels - OEM steelies, Mini Cooper 5 spoke, and Toyota TTE Pittlane. I personally left my TPWS sensors on the steelies (which I will probably never use again). The sensors would work on the Mini wheels, but not on the Pittlanes.

You can definitely grab a set of 08 sensors and use them. Any decent tire shop (and of course the dealerships) can do the reprogramming when you switch between tires. My local dealership charges $90 to do the reprogramming, but I would bet that tire shops charge way less.

The primary purpose of the system is not safety, but rather environmental. I heard a statistic at an RFID conference that if every car in the world was running at proper inflation (rather than some percentage being low) CO2 emissions would be reduced by (if memory serves me correct) 50 million tons per year.

I have been doing some reverse engineering on the TPWS ECU, and have a solution (not yet implemented) to the multiple sets of wheels, choosing to run at higher pressure, using different sized rims, etc. issues.

I believe that I can intercept the data between the sensors and the module and relay massaged data. By doing this I can have my module memorize multiple sets of sensors and allow calibration of the data from those sensors (i.e. adjust for running at higher pressure, etc.) The data that my module would pass, would be repackaged with the ID of the original sensors and with the pressure normalized to what the OEM system was calibrated to.

This would also allow for a more realtime display of the tire data (either a simple display with 4 bicolor LEDs, or a more elaborate LCD display showing pressure and temp for each of the 4 tires.

[SailDesign]

...
I have been doing some reverse engineering on the TPWS ECU, and have a solution (not yet implemented) to the multiple sets of wheels, choosing to run at higher pressure, using different sized rims, etc. issues.
...

You mention higher pressures a couple of times here. Is there something the TPMS system does with that? I'm running a bit high, and no trouble with the TPMS light.
:iono:

[CTScott]

You mention higher pressures a couple of times here. Is there something the TPMS system does with that? I'm running a bit high, and no trouble with the TPMS light.
:iono:

The system does detect both high and low. I just checked the service manual for the high limit, and I don't any hypermilers are going to get close to it: 87psi

[SailDesign]

The system does detect both high and low. I just checked the service manual for the high limit, and I don't any hypermilers are going to get close to it: 87psi

I think i'm safe, then. :laugh:

[gammaray]

Similar to what was stated above....my dealership charges $85 for the transfer, and a local tire establishment said they would charge $40.

[mikenacarato]

who ever runs 87psi in their tires is plain stupid.

anywho, i would just do the bypass and dont worry about it every agin. :) its pretty easy to do if you follow the diy.

[WolfWings]

Don't forget, your tires can end up at a MUCH higher pressure once they heat up, compared to the cold inflation pressure. 87psi is ALMOST in the realm of feasable if you started at, say, 60psi for hypermiling on a highway trip from Canada to Mexico or something equally silly. :D

[Yaris Hilton]

No, they're not going to heat up that much. Pressure of a confined gas is proportional to absolute temperature, i.e., degrees Kelvin. Add 273 to the current temp in degrees Celsius. You're not likely to see your tires go up by nearly half on that scale unless you're driving on The Highway To Hell.