Tire Pressures

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SETI20
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Tire Pressures

Postby SETI20 » Sun Jan 17, 2016 1:01 pm

I'm having some odd discrepancies with my TPMS.
I've inflated my tires to 35PSI (a little low because of the snow) but my TMPS screen (2007 LE with Navi) shows wildly different measurements ranging from 38 PSI all the way down to 31Psi. I've tried to be very accurate when I inflated them. I have a compressor and inflator with a dial on it and they seemed pretty much the same on all 4 corners to me.

How accurate is this supposed to be?


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eieio
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Re: Tire Pressures

Postby eieio » Sun Jan 17, 2016 1:42 pm

SETI20 wrote:I'm having some odd discrepancies with my TPMS.
I've inflated my tires to 35PSI (a little low because of the snow) but my TMPS screen (2007 LE with Navi) shows wildly different measurements ranging from 38 PSI all the way down to 31Psi. I've tried to be very accurate when I inflated them. I have a compressor and inflator with a dial on it and they seemed pretty much the same on all 4 corners to me.

How accurate is this supposed to be?
I don't know how accurate it's supposed to be, but is there any pressure where the TPMS does not act weird?
Also, have you checked all the tire pressures with a different guage to verify that they are correct?

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smj999smj
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Postby smj999smj » Sun Jan 17, 2016 1:48 pm

I use an Accutire digital tire pressure gauge like the one linked to below. It does a pretty good job and is accurate to 0.5 PSI. When I adjust the tire pressures, the most I'm off according to the tire pressure monitor is only 1 PSI.

http://www.autogeek.net/acstditigu.html ... Aokp8P8HAQ

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SETI20
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Postby SETI20 » Mon Jan 18, 2016 1:39 pm

There is one tire that always seems to be off more than the others. Last summer it was angrily flashing "low pressure" at me, and then just went away.

I'll grab a second gauge to just double check as it seems the TPMS is supposed to be relatively accurate. Thanks guys.

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Touchdown
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Postby Touchdown » Mon Jan 18, 2016 3:53 pm

Here's another idea-
I don't know if Discount Tire is up there or not, but try to find a tire place that can re-sync all of them for you.
Maybe the error is with the on-board app and not something physical.

DanJetta
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Postby DanJetta » Mon Jan 18, 2016 5:34 pm

Mine have never been accurate and the pressure displayed changes based on many factors, including temperature, speed, and the location of Mars in relation to Mercury. My digital gauge will say 35psi all the way around while the screen ranges from 31psi to 38psi.

While the sensors are inaccurate in what the actual pressure is, they usually are accurate at measuring when one tire's pressure is way off from the rest.

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Touchdown
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Postby Touchdown » Mon Jan 18, 2016 8:26 pm

While the sensors are inaccurate in what the actual pressure is, they usually are accurate at measuring when one tire's pressure is way off from the rest.
This is so true! I had the low tire light come on last summer while on the highway doing 85. By the time I pulled over (which was right away) the tire pressure was around 15psi. If I didn't have the sensors, God knows what could have happened to me and my family at that speed.
I suppose if you never get them perfect, think of it as a fail-safe for stuff like that! :)

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eieio
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Postby eieio » Tue Jan 19, 2016 9:10 am

Touchdown wrote:
While the sensors are inaccurate in what the actual pressure is, they usually are accurate at measuring when one tire's pressure is way off from the rest.
This is so true! I had the low tire light come on last summer while on the highway doing 85. By the time I pulled over (which was right away) the tire pressure was around 15psi. If I didn't have the sensors, God knows what could have happened to me and my family at that speed.
I suppose if you never get them perfect, think of it as a fail-safe for stuff like that! :)
it would be disconcerting to me to have a system that indicates incorrectly like that
i'm happier to have the alternate method where it does not indicate individual pressures, but signals when a pressure is different from the rest

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SETI20
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Postby SETI20 » Tue Jan 19, 2016 3:34 pm

True enough, I had one tire go soft once, but it's been inexplicably holding pressure just fine since. TPMS alerted me to that.

On the other hand, I've also had the TPMS alert me, but when I went to check, tire pressure was just fine. So I definitely think one of my sensors is wonky.

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smj999smj
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Postby smj999smj » Wed Jan 20, 2016 11:24 pm

The sensor batteries tend to last about 6-7 years...some longer and some not so long. As the batteries get weak, the will start to trigger the TPMS light and a low voltage code. When the weather gets cold, the weak batteries will tend to act up more often; as you drive the vehicle and the air inside the tire gets warmer, the sensor will start working again.

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SETI20
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Postby SETI20 » Tue Feb 02, 2016 3:33 pm

^^ Useful, thanks!

Definitely notice more differences now that we have warmer weather.


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