Where's Zepcom when you need him??? Is it possible you may have a leaking valve stem or a slow leak in the tire?? I'd check the tire pressure manually for starters.

 

My car will trip for one of the rears on cold days, even though the DIC says they're both the same pressure.

Does the warning go away after you've driven a few miles and warmed the tires up?

 

There was no warning, but the pressure did go up 2 pounds as the tires warmed, but so did the rest, so it was still several pounds off.

 

Then it's probably low by a couple pounds. All my tires are down about 4psi from sitting over the winter, haven't filled them up yet, but they're still within the threshold after warming.

Tires will lose a little pressure if they've sat over a season in my experience.


EDIT: Well, I suppose I should say they're "losing" pressure, but it's really more likely that you store them when it's around 50*F for winter, then pull them out the first time you get some 50*F weather back. So it's just the cold air that you put them on at that seems to be causing this.

 

Maybe they lost air in storage, but after the relearn procedure dropped them down several pounds I promptly filled them back up to 40. My manual gage says it was at 38 after work, but the dash said 30.

 

Hmm... That is a little suspect... I think that they're slower to read than your hand gauge, but not certain of that fact...

 

I've heard of TPMS sensors reading as much as four p.s.i. lower versus a manual gauge, but never eight p.s.i. Maybe it has to do something with the sensor. This is where my knowledge ends and ignorance begins, hopefully someone with more experience (ZEPCOM) will add their $.02.

 

Sorry I'm late to the party, fellas! I'll try to contribute.

As said above, while in storage, the tires will somtimes lose some air. Depends on many factors, but mostly related to the porous nature of aluminum (rims) and the quality of the bead / seal.

I would recommend you put maybe 50-100 miles on them and check pressures again. The car's tpms only 'takes a reading' when the wheels are in motion or pressure drastically drops (which is directly related to the tpms learn procedure!) ... so a bit of mileage may get them better in sync with what your manual gauge says.

If that doesn't work, I would recommend you stop by a few tire shops in your area and get peices for qty 4 'tpms maint kits'. Basically over time (usually after you mount / dismount tires, but could apply here) the copper 'washers' that seal the tpms sensor to the rim and valvestem hole get too compressed and start to lose air. Could very well be what you're describing.

I've seen $6-$10 on average per tire... and iirc it requires breaking the bead/seal on the tire to install the maint kit... but the tire places would know best. If so, consider a road force balance if possible.

Hope this helps!

Zep

sent from my EVO4g via Tapaftalk

 

Well, today it seems to be reading fine. But yesterday it was just plain low. I filled them up to read 40 on the dash after the relearn on Sunday. Then yesterday it was at 30 and moved up a bit when I was driving. And today it seems ok without adding any air.

Normally, my dash reads a couple pounds higher than my hand gauge does. I'll just keep an eye on it, I guess.

 

The maintenance kit that Zepcom is referring to also called a "service pack" and they basically replace everything but the sensor itself. You should not pay more than 3-5$ for these kits/packs each.

Glad to hear that your problem has resolved itself for time being. FYI to answer your OP, the TPMS sensors will function normally regardless of battery life, untill the battery is dead. At that time it will either read no air pressure, or continue to read the last read pressure and not change. The average battery life of these sensors is 5-7 years.

FWIW, I am a Michelin Certified Tire Installer and TIA (Tire Industry of America) Certified. In the next couple years, I am thinking a lot of people will be replacing their sensors due to a dead battery. I hope these people don't run to the stealer-ship for replacements though!

 

help my brain is exploding.

Been searching for issues similar to mine. I feel like my batteries must be dying or maybe something is loose?

for a good couple weeks my front left tire was acting strange. it would start fine at 38, then you could watch it go down fast like the tire had a huge hole in it but it usually stopped around 4-8 and sometimes would immediately jump back up to 38... (annoying chimes between of course)
it was really sporadic, at first i thought there was a pattern but then it would change... somedays it wouldnt ding. sometimes i could go 20 miles between faults. others it would trip back and forth what seemed like every 5 seconds (which is incredibly annoying)

then it stopped for a week or so. then the front right started going off, only the behavior was totally different, either its not an issue, or it is. it would go off somedays, others it wouldnt bother me at all, but when it did it would just stay low all day and it only goes to the 20s... now both are at it, but the behavior is pretty consistent between the 2, both acting like the front right as described above except the left still goes as low as 4 psi...

totally strange and i havent found other threads similar, but i didnt want to start a new post because this one's title seems close enough, if this doesnt get any attention then i'll start another thread...

I suppose a re-learn wont hurt and maybe i'll do that, but i'm due for a rotation so i'll bring it in and have the tire shop rotate and re-learn.

zepcom? gopher? you guys got any ideas on this?

maybe you've seen a similar post and can direct me there???

 

Mine seemed to straighten out and has been reading fine ever since. Still on the original batteries.

 

If your having the wheels rotated from front to back, and the TPMS re-learned at the service center, *if* the problem then shows up at the rear wheel location, you'll then know that you have 1 or 2 worn out transponders.