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Tire Pressure Monitor Implications

Discussion in 'Gen 2 Prius Fuel Economy' started by GreenMachine, Dec 19, 2005.

  1. GreenMachine

    GreenMachine New Member

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    According to the Owner's Manual for the '06 (thanks to XLR8 for emailing me the pictures of the relevant pages) there are several things that make the tire pressure monitor report an alert.

    Things that catch my eye.

    If the tire pressure is 7.3 psi above the specified level. (Does this mean above 35 front and 33 rear so anything over 42.3 front and 40.3 rear won't work?)

    Use of non-genuine Toyota wheels and even with genuine Toyota wheels, some tires won't work!

    Use of tire chains

    Certain Window Tints

    There are some real questions here with regard to modifications which many PC members have developed and recommend for the '04-'05.
     
    #1 GreenMachine, Dec 19, 2005
  2. aaf709

    aaf709 Ravenpaw of ThunderClan

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    I was curious about this. Is the monitor one that shows an actual tire pressure on the display or a "Good/Oh-oh" indictor (similar to an Idiot Light). If the latter, does it indicate when the pressure goes below a certain amount? If so, is that amount set by the driver (through initializing, for example) or preset?
     
    #2 aaf709, Dec 19, 2005
  3. naterprius

    naterprius Senior Member

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    This all sounds bogus. I'm fairly certain the TPMS can be reset to different "baseline" pressures by setting the pressure where you want it, then pressing the reset button on the dash. All the sensor does is transmit the pressure.

    Moving the TPMS sensor the new wheel should work as long as the wheel and tire provide clearance for the sensor.

    Chains may impact the momentary pressure in the tire, causing false alarms. Big deal. You are in 6 inches of snow anyway, check the pressure when you put the chains on and keep driving.

    If you are worried about blocked RF from metallic window tint, get non-metallic like I did. Avoids potential cell phone and GPS issues as well.

    Nate
     
    #3 naterprius, Dec 19, 2005
  4. hdrygas

    hdrygas New Member

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    The window tints has been around since 04. The caution on the tire chains for the 04 is only for the rears and to remove the wheel covers or they will be scratched.
     
    #4 hdrygas, Dec 19, 2005
  5. GreenMachine

    GreenMachine New Member

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    These are specifically related to the tire pressure monitor.
    Here is the jpg of the page from the manual

    [attachmentid=1474]
     

    Attached Files:

    #5 GreenMachine, Dec 19, 2005
  6. GreenMachine

    GreenMachine New Member

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    BTW Nate, I tend to think you are right for the most part. But I do find the wording in the manual interesting.
     
    #6 GreenMachine, Dec 19, 2005
  7. hdrygas

    hdrygas New Member

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    That is interesting. I guess that some types of window tinting must impede radio signals. Those are very different from the cautions in the 04 manual.
     
    #7 hdrygas, Dec 19, 2005
  8. DocVijay

    DocVijay Active Member

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    Well, we will all soon find out. I'm swapping over to 17" Scion tC wheels, AND I'm getting the windows tinted. Soon we will all know for sure. I don't think I'll be running too high a pressure.

    I don't think the pressure issue will be an... well an issue. THat's what the reset button is for. It says in the service manual that it should be reset "when replacing tires with a different pressure," which leads me to believe that you can switch tires.

    Besides, the SE area still offers optional 17" wheels. They wouldn't do this and allow the factory TPMS to be disabled.
     
    #8 DocVijay, Dec 19, 2005
  9. GreenMachine

    GreenMachine New Member

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    I can't understand why some tires won't work. How does the system know what type of tires are on the car?

    That goes for the wheels too -- just makes no sense.
     
    #9 GreenMachine, Dec 19, 2005
  10. acousticbiker

    acousticbiker New Member

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    Does the manual discuss what is involved with replacing tires? I'm getting an '06 Seaside #8 in early January and would like to replace OEM tires with GY Assurance Comfortreds. I doubt the guys at Big O Tires will know offhand, so I'd like to know what will need to be done to ensure continued functioning of the TPMS.
     
    #10 acousticbiker, Dec 19, 2005
  11. GreenMachine

    GreenMachine New Member

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    I don't have my '06 yet nor have I seen a manual. The page in the manual I posted above was sent to me by XLR8 in response to my concern about the implications. I will email him and ask if the manual covers this.

    Since the manual does say, even with genuine Toyota wheels, some tires might not work, I would think it would behoove them to say which ones will work. Or, at least, what the specs are for acceptable ones.
     
    #11 GreenMachine, Dec 19, 2005
  12. naterprius

    naterprius Senior Member

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    Take it from me. I've had RF based TPMS in my Prius for over a year. I have tinted windows. I have replacement tires. I have yet to install tire chains, but would not hesitate to do it.

    Nate
     
    #12 naterprius, Dec 20, 2005
  13. IFixEm

    IFixEm New Member

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    Nate is correct on this....the base line setting on vehicles with similar systems use the spare tire presure/temp as the base. The Prius will use tire #1 as a base at the time of initilization. It remembers this set psi and monitors 1-4 vs. the set base. All you will have to do is set tires to your spec ( I like 42/40, but each to thier own), press and hold the reset button and never look back. Tire /wheel swaps should be the same procedure. Where folks will get into trouble is if they swap only 2 tires out with different rotations per mile specs. Even then they would need to be off conciderably to pop a warning light.
    Regards, Mike
     
    #13 IFixEm, Dec 22, 2005
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