False Tire PSI Reading

[mtofell1]

All I can find on searches is TPMS questions and this isn't really one of those.... I don't think.

We've had a cold snap and yesterday the light on my 2014 Ram started telling me I had a low tire. So, I stopped into the shop and the kid told me the front/right only had 35# (should be 60). I thought it was strange since my truck tells me all 4 corners and it said 55. So, today I go check to see if it's lost any and every time with 3 different hand gauges it tells me 30ish at first and when I try a couple more times it pops to 60. The interior gauge also is telling me 60.

My question is can valve stems be bad and not produce a correct reading at first attempt? I've never had this happen before but since my 3 hand gauges and tire store kid's hand gauge all do the same thing I'm thinking there is something wrong with the tire. The tires in question are only a few months old.

[Beverley_Ken]

Is it possible that there is a bit of moisture on or in the sensor, valve stem that froze and affecting the reading of both the sensor and external gauges. A little heat buildup and motion would free it up
Maybe an argument for using 99.9% nitrogen (it’s apparently drier) than regular compressed air.

Ken

[fcooper]

I would try a new valve stem core in the existing valve stem.

[TurnThePage]

I'm gonna say that maybe the actual valve stem is malfunctioning due to cold, corrosion, or crud.

[FishOnOne]

ScottG wrote:
my 2015 Challenger uses battery-free sending units in the tires.

What do they use for power?

[Etstorm]

I was told by a tire guy that the TPMS works on WiFi/Bluetooth. Any WiFi or blue tooth in the vehicle CAN interfere and give a false reading.

Cell phone, computer, etc

May not be the case here but worth checking

[Charlie_D_]

Me Again wrote:

New sensors are part of the valve stem now. Cost 20 some dollars each, depending where you buy them.

Interesting. Haven't heard or seen those types. My current and former vehicles all have stems replaced and existing TPMS reused when tires get replaced.

[mtofell1]

It's still holding at 60 through today. It's just strange that my TPMS went off (likely due to cold and the psi dropping a bit) and then tire shop kid said it had 30 in it. fwiw, the tires are only a few months old and I hadn't ever checked the pressure yet.

Thanks everyone,

[Grit_dog]

It’s not the tire, unless it’s leaking.
Does it have 30psi or 60? 30 is half flat, 60 is full. Easy to tell.

[ScottG]

Not sure about your 2014 Ram but my 2015 Challenger uses battery-free sending units in the tires. The only down side of these is they aren't instantaneous when sitting still and making pressure changes. The tire has to make a few revolutions to report a change in pressure. I get an update after backing 10~15'.

EDIT: It looks like 2014 & 2015 RAMs still use batterys.

[Me_Again]

Tvov wrote:

mtofell1 wrote:
....

My question is can valve stems be bad and not produce a correct reading at first attempt? ...

Valve stems certainly can be "bad"! And they are very easy (and usually inexpensively) replaced at most any shop or tire store.

Dirt, gunk, sludge or whatever can muck up a valve stem, and it is usually easier and quicker to just replace it. If there is a piece of dirt in the valve stem, it could be jamming randomly the movement of the valve, explaining weird psi readings.

New sensors are part of the valve stem now. Cost 20 some dollars each, depending where you buy them.

[Tvov]

mtofell1 wrote:
....

My question is can valve stems be bad and not produce a correct reading at first attempt? ...

Valve stems certainly can be "bad"! And they are very easy (and usually inexpensively) replaced at most any shop or tire store.

Dirt, gunk, sludge or whatever can muck up a valve stem, and it is usually easier and quicker to just replace it. If there is a piece of dirt in the valve stem, it could be jamming randomly the movement of the valve, explaining weird psi readings.

[FLY_4_FUN]

I wonder if its just a issue with the cold temps allowing for false readings on the TPMS senders? I had many "false alarms" on my minivan with TPMS at extreme temps especially if parked up against a curb. Could there be some moisture in the valve stems causing errant readings on your gauge? Perhaps get it into a heated shop for a few hours and try your readings again. My 1 ton usually sits at 60-70psi for towing but was horrible on snow. I finally got smart and aired down to 45psi for winter driving as my contact patch at "towing specs" was tiny and dangerous! Hopefully this is just a weather issue and not batteries dying in the senders.