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-   -   Is TPMS off by about 3 psi? (http://www.jeepgarage.org/f109/is-tpms-off-by-about-3-psi-14567.html)

JoeSchmoe007 10-30-2010 05:34 PM

Is TPMS off by about 3 psi?
 
My old trusty(?) tire pressure gauge shows 33 and EVIC shows 36

Anyone else noticed the same?

moosehead 10-30-2010 06:14 PM

Re: Is TPMS off by about 3 psi?
 
you're doing it wrong

Technosavant 10-30-2010 07:57 PM

Re: Is TPMS off by about 3 psi?
 
Pressures are supposed to be checked when cold. TPMS reports when you've been driving, and that's going to be higher due to heat in the tire from driving.

Really, though, the TPMS equipment usually isn't as accurate as a quality tire gauge. Good enough to let you know if things are going pear-shaped while driving, but they don't take the place of periodic checks with a regular gauge.

JoeSchmoe007 10-30-2010 08:04 PM

Re: Is TPMS off by about 3 psi?
 
I checked with gauge and compared with TPMS when cold.

ryorde 10-30-2010 08:20 PM

Re: Is TPMS off by about 3 psi?
 
I’m not sure about the TPMS sensors on the Jeeps, but most TPMS sensors only report the pressure when the tire is rolling to save battery power. The EVIC is just storing the last reported pressure. Easiest way to test would be to let a little air out of one tire and see if the EVIC updates.

JoeSchmoe007 10-30-2010 08:28 PM

Re: Is TPMS off by about 3 psi?
 
I'll double-check tomorrow

GlowingGhoul 10-31-2010 09:04 AM

Re: Is TPMS off by about 3 psi?
 
Wheel doesn't have to be moving for TPMS on the WK2.

My TPMS reads exactly the same as my digital gauge.

The pressure in my 20's was 42, cold, when they should've been 36.

As I released pressure from the tires, TPMS updated in real time.

On a seperate note, the drive smoothed out a lot after dropping the 6PSI. It was teeth rattlingly brittle before that.

Bmwister 10-31-2010 12:17 PM

Re: Is TPMS off by about 3 psi?
 
Make sure you check tire pressure with a goo dial gauge rather than the "pencil" type. A good gauge is about $15-$20 if you want a high degree of accuracy. If the TPMS is like others, it shows the last reading taken; I would surmise it should match your gauge (a good gauge) if you look at the EVIC reading and the immediately do a physical pressure check.

Milous 10-31-2010 02:06 PM

Re: Is TPMS off by about 3 psi?
 
Quote:

Originally Posted by GlowingGhoul (Post 293486)
My TPMS reads exactly the same as my digital gauge.

Same here, in fact it has been dead accurate on all of the GC's I have owned over the years. I have a digital readout gauge which is much easier to use than dial types. I set all my pressures at 33.1/33.2 which allows all of the EVIC readouts to be exactly the same. Can't do this easily with a dial gauge.

JoeSchmoe007 10-31-2010 02:57 PM

Re: Is TPMS off by about 3 psi?
 
I just double-checked and it's the same - TMPS shows 3 PSI more than my dial type gauge. Of course dial type gauge can be wrong

Milous: what kind of digital readout gauge do you have? What is the brand/model?

Milous 10-31-2010 03:19 PM

Re: Is TPMS off by about 3 psi?
 
Quote:

Originally Posted by JoeSchmoe007 (Post 293635)
Milous: what kind of digital readout gauge do you have? What is the brand/model?

Accutire, exact same as: Michelin 12279 Digital Programmable Tire Gauge

$25 shipped at Amazon:

http://www.amazon.com/Michelin-12279...=pd_sim_auto_5

http://ecx.images-amazon.com/images/...FL._SS500_.jpg

JoeSchmoe007 10-31-2010 05:02 PM

Re: Is TPMS off by about 3 psi?
 
I found another old dial gauge in my toolbag. It matches everything TPMS screen shows exactly EXCEPT rear left tire, so I deflated all tires by 3 PSI. All tires show 33 PSI on dial gauge. On EVIC everything except rear left shows 33, rear left shows 36.

Does spare tire also have TPMS sensor? If this is the case - I think maybe computer is reading sensor from the spare instead of rear left tire.


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