official TPMS info from Toyota tech training class

[galaxee]

edit: briefly updated to correct the post, more info to follow.
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short answer: the 06 has direct TPMS only.

long answer: so the training manual we referenced when originally writing this post did not have a description of the new direct TPMS, and instead was describing the old system. based on the info we had, if a car had the reset switch along with the direct sensors, it had to have both systems.

the old system had a stored "ideal tire pressure" value pre-programmed into the TPMS ECU that differed for each model, and could not be set to user-specified values. this is why there was no reset button on the old direct-sensor systems, and why we concluded that there were 2 systems.

the new system, which is on the 06 prius, allows for user-defined tire pressures, which for us and our slightly more inflated tires for better mileage, is great. hence the reset button for the direct sensors. you can set your own tire pressure and instead of waiting for the pressure to drop 25% below the specified pressure (which would have been whatever is in the door sill, i think it's 35/33) rather than getting a warning light when the pressure dropped to 25% below your preferred 42/40.

still the same principle aside from that. sensors integrated with the valvestem that measure pressure in your tires and transmit the info to a TPMS antenna, which is wired into the TPMS ECU. it sends a warning light on the dash when you lost 25% of your tire pressure.

sensors are run on Li-ion battery that lasts about 10 years and are in sleep mode until they are installed to prevent battery rundown while sitting in your local parts department.

there is no "main/2nd" switch in the 06 prius, as i've been told. this isn't surprising, i think there's only one or maybe 2 models out there that do have the switch. this means getting a second set of wheels with snow tires or the like on them is going to be a real pain in the butt and quite expensive. you'll have to have the TPMS ECU reprogrammed at the dealer twice a year, it requires the scantool. plus you'll have to have the 7-digit code written down for each of the sensors, including the ones that are installed in the OEM wheels, which means breaking the seal on the OEM tires and reinstalling the tires. it's going to be cheaper to have new tires mounted at the change of seasons rather than having a spare set of wheels.

DocVijay asked the question below about using a different angle sensor for non-OEM wheels. theoretically it could work, but he's going to bravely be the guinea pig here and see what the results are. all in the name of discovery! let's give the guy a pat on the back.

i have yet to see the reset/re-initialize info, will post that too as soon as i get my hands on it, which will be later on tonight.

i am glad DH is the tech and i'm not, having to learn about all these new things being sent out all the time on new cars would be a real pain!

[bobr1]

Galaxee - thanks for the excellent and detailed information!

- Bob R.

[hdrygas]

Thank You!! It is great to see information like this. Bit by bit one can appreciate the degree of engineering that goes into this car. Thank You again. You are defiantly cool.

[galaxee]

you're very welcome. i do what i can to contribute.

and i have been deemed "cool" too... what a great day

[galaxee]

one more thing. the valvestem sensors are run on batteries, which last around 10 years. expect to replace them every 10 years or thereabouts.

[hdrygas]

Originally posted by galaxee@Jan 22 2006, 06:19 PM
one more thing. the valvestem sensors are run on batteries, which last around 10 years. expect to replace them every 10 years or thereabouts.

[snapback]195600[/snapback]

In the tires? What an idea, but 10 years, I guess I have only once kept a car for 10 years.

[Tideland Prius]

thanks for the info

one question, couldn't the 06 owners re-initialize the settings when they pump all 4 to 42/40 or what not?

[galaxee]

yep. i put that in this section:

re-initialize is used if you rotate, replace, or repair tires. if you're increasing the pressure in ALL 4 tires, also use this procedure.

increasing pressure in all 4 tires would include the situation of increasing the pressures to 42/40.

[TonyPSchaefer]

Originally posted by galaxee@Jan 22 2006, 08:19 PM
one more thing. the valvestem sensors are run on batteries, which last around 10 years. expect to replace them every 10 years or thereabouts.

[snapback]195600[/snapback]

Oh great, another stinkin' battery to worry about replacing in ten years!



Great post, G.

[galaxee]

Originally posted by TonyPSchaefer@Jan 22 2006, 11:51 PM
Oh great, another stinkin' battery to worry about replacing in ten years!



Great post, G.

[snapback]195737[/snapback]

suppose that'll further reduce the chances of ever making your money back on a prius, huh?

actually, you have to replace the whole sensor when the battery dies. and i have more info to post here once the cat gets off my chest... which may be a while.