Aftermarket TPMS

Discussion in 'Gen 4 Prius Accessories and Modifications' started by dslomer64, Oct 11, 2019.

  1. dslomer64

    dslomer64 Member

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    A few months ago a package arrived with a TPMS inside but with no included invoice or the like. Who the heck sent it and why no identification?

    I let the new accessory languish in its box for a few months while I decided whether to just pitch it, partly because
    the installation and usage instructions are written in Chinese-influenced English and so are very difficult to understand.

    But after having a flat tire on my Non-Touring IV and finding a video on installing what actually looks to be the same TPMS, I decided to remove the old and install just the new valve stem caps (and not the accompanying locking nuts and o-rings) and see what happens.

    The danged thing works and seems to be accurate (after one day's use!) based on the usual 2-psi difference between my air gauge and those of tire stores.

    Here's the thing. I test drove both a 2017 Camry and then a Prius, same day. The Camry had a built-in TPMS. I didn't notice the lack of one on the Prius since I had just seen one (but in the Camry). Having no built-in TPMS is outrageous, as I pointedly told Toyota in a survey. Maybe they sent me the TPMS.

    A warning light is not a TPMS. One recent morning, I found a tire completely flat. The light hadn't come on during de-pressurization. Nor did it come on when I got into the vehicle to check this very thing. Toyota service gave reasons that did not instill confidence.

    So I installed the TPMS soon after.

    It tells each tire's pressure and temperature. Warning alarm parameters for not only insufficient but also excessive pressure can be set. It's solar powered and, when insufficient sun shines, USB charger equipped.

    I know that such valve-stem add-ons can allow air to escape, but the "console" will alert me, in which case I will tighten the offending cap. I will install all the o-rings (that the instructions overlook) and locking nuts with another occurrence on any tire. Third leak's the charm-ing death knell. Out they go.

    With my above thoughts in mind, I can't think of a reason why this is a bad idea.

    However, the locking nuts, if truly necessary, would be a deal-breaker. They're inaccessible with the wheel covers in place and would be very difficult to tighten and loosen as required even with the wheel covers removed. If I decide to discard them, I'd have to have in-wheel sensors installed because now that I finally have TPMS, I can't do without.

    And why DID Toyota think TPMS unnecessary??

    We

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  2. wjtracy

    wjtracy Senior Member

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    Not sure I am following the story exactly.

    2006 was the first year Prius had TPMS. My car has it.
    Toyota did not give Prius a visual read-out of the tire pressures , but we do have the warning light.
    Most 2006 should have replaced TPMS by now...I had a two tires stay alive until this year, but had 2 go bad.
    The battery goes bad and need new TPMS unit inside the tires, or you can buy the cap style aftermarket with readout..
     
  3. Salamander_King

    Salamander_King Senior Member

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    Is this about 2006 Prius or about Gen4 as this thread is placed?

    In either case, OP must be talking about external TPMS sensors that replace the valve stem cap and a receiver with tire pressure and temperature display. If so, there is absolutely no reason to install those "anti-theft" locking nut for those external sensors. No one is going to steal those ugly caps. lol. I have them on my tires since I switched to my winter wheels and tires last fall, and continue to use them on my summer OEM wheels and tires. Yes, I agree that the utility of being able to see each tire pressure in real-time is a very nice thing.

    IMG_20181115_105448-COLLAGE.jpg
     
    #3 Salamander_King, Oct 11, 2019
    Last edited: Oct 11, 2019
  4. sam spade 2

    sam spade 2 Senior Member

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    I think there are some mis-conceptions hiding in that long post.

    One is: You seem to think that some TPMS systems operate full time.....even when the car is OFF.
    That is NOT the case. The little batteries in the transmitters would go dead WAY too quickly.

    The book with my "external" system specifically warns to visually check the tires before driving off because it takes a short time before the system starts receiving "new" data.
     
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  5. Fester

    Fester Active Member

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    A ScanGauge will display both tire pressures and temperatures using the existing TPMS sensors. The single light on the dash is there too, but the Prius does internally record this data which is displayed by programming the X-Gauge commands into the ScanGauge.
     
  6. Salamander_King

    Salamander_King Senior Member

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    I bought ScanGauge II for this, but I never got using it. Connecting the OBDII, securing the guage and cable, programming the X-Gauge... was just too much after using external TPMS that took only replacing valve cap with the external sensor and placing the receiver on the dash.

    Also, the good thing about external TPMS sensor is that when you rotate tires, all I have to do is to switch the sensor to correct location FR, FL, RR, RL. With Scan Gauge using OEM TPMS sensors, how do you track the correct wheel to display on the gauge?
     
  7. Fester

    Fester Active Member

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    Just edit the XGauge code name, I use TP1,2,3,4, etc. which I know as front left, front right, rear left, rear right, in sequence.
    To ID the TPMS and which tire (say after a rotation..), just park with one side in the sun and place something to block the sun from the tire...whichever pressure decreases as the tire cools is the one.
     
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  8. Salamander_King

    Salamander_King Senior Member

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    What I meant to ask was changing display order on the ScanGauge display easy to do, so that 4 values displayed on the ScanGauge is corresponding to FL=UpLeft, FR=UpRight, RL=BottomLeft, RR=BottomRight?
     
  9. dslomer64

    dslomer64 Member

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    I do still own a 2006 but I also have a 2017. When I wrote that I had found "a flat tire on my Non-Touring IV" without mentioning 2017, I assumed that ruled out '06, since packages I, II, III, etc. weren't offered then.



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  10. dslomer64

    dslomer64 Member

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    I wrote, "A warning light is not a TPMS," but I stand corrected: "TPMS report real-time tire-pressure information to the driver of the vehicle, either via a gauge, a pictogram display, or a simple low-pressure warning light."--Wikipedia

    What I really meant, or how I'll say it now, is that "true TPMS", in 2017 (or 2020), really shouldn't bring to mind a "simple low-pressure warning light". The ability to have "real-time tire-pressure" tell me exactly which tire is low and by how much isn't a luxury, especially not in sub-zero or near-100° weather.

    And I'd like to know, as I drive out of my friendly Toyota dealer, if they set the pressures as I asked, which they usually don't.

    So make it an option. Just don't exclude it altogether.

    Having concluded my rant, which assumed the 2018-2020 Prii lack "true TPMS", please strike me gently (not the face!) if my assumption is incorrect (which I sincerely hope it is!).

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  11. wjtracy

    wjtracy Senior Member

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    Yes many of us would like to see the tire pressures.
    Not sure which Prius models have that now, if any.
     
  12. Salamander_King

    Salamander_King Senior Member

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    NONE!
     
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  13. donbright

    donbright Member

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    were you suspicious someone is trying to track your movements?
     
  14. dslomer64

    dslomer64 Member

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    I was reviewing this thread because it's related to my next question and I came across this.

    What did I write to cause you to say what I "seem to think"? I didn't say anything that would suggest that, unless you're talking about the built-in TPMS light.

    While I didn't and don't think that the built-in system "operates full time", I did expect it to show (very, very, very) low pressure upon or shortly after pushing Start. It didn't. I filled the tire enough to safely drive the 2 miles to the dealer. Light never came on. And I didn't mention the aftermarket console's on-off switch, so I didn't mention turning it off. But I didn't and don't leave it on (intentionally!).

    When I ran over a big, sharp object in the dark 10 years ago, the tire went immediately flat and--trust me, I remember every detail, having had to change that tire alone and one-handed, with my recently-repaired right rotator cuff arm in a sling--the TPMS light came on immediately, or after an imperceptible delay.

    I suppose that, early in the intervening 5+ months, I may have edited out what sam spade is referring to. I do edit just about all my posts, but usually for format and syntax.

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  15. sam spade 2

    sam spade 2 Senior Member

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    It absolutely should show a low pressure immediately upon starting.....or almost immediately.
    Unless you have made some modification that defeats that.

    It sounds to me like yours is not working right.
    It would be easy enough to test.
     
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