[mrsastrakhan]

Hi!

Car: 2012 with 4k miles on it (ie pretty new). Goes in for its 3500mi first service on Thursday.

Just got caught in a HUGE rainstorm (as in, had to pull over and wait it out because I couldn't see).

After I moved on, the TPMS light came on. Inspected all tires visually and none are flat or noticeably soft.

Q1: Is it common for the sensor to fail if wet?
Q2: how do I check pressure at a gas station air pump? I know how to put air IN the tires (hardly brain surgery) but I always struggle trying to read the gauge and not let air back out (I can hear it hiss). Sorry for this ridiculously girly question but hey - if I don't ask, I'll never learn

 

[foxrider68]

Hi!

Car: 2012 with 4k miles on it (ie pretty new). Goes in for its 3500mi first service on Thursday.

Just got caught in a HUGE rainstorm (as in, had to pull over and wait it out because I couldn't see).

After I moved on, the TPMS light came on. Inspected all tires visually and none are flat or noticeably soft.

Q1: Is it common for the sensor to fail if wet?
Q2: how do I check pressure at a gas station air pump? I know how to put air IN the tires (hardly brain surgery) but I always struggle trying to read the gauge and not let air back out (I can hear it hiss). Sorry for this ridiculously girly question but hey - if I don't ask, I'll never learn

You need to buy your own tire gauge and keep it in the car. Visually inspecting your tires will tell you nothing. Once you have your own gauge you can pump them up and check them yourself.

 

[mrsastrakhan]

Which is great to know for the future - but right now, I need to check the tires and fill them so that I can drive on safely, which means I need to use what I gotz... which is the nearby gas station. So, I repeat the question: what's the best way to do this using the gas station air pump? Thanks!

 

[fortinv]

To answer Q1: I have driven in very heavy rain several times, never had the TPMS light come on.

 

[RobMunach]

Which is great to know for the future - but right now, I need to check the tires and fill them so that I can drive on safely, which means I need to use what I gotz... which is the nearby gas station. So, I repeat the question: what's the best way to do this using the gas station air pump? Thanks!

Most gas stations will sell tire pressure gages..

 

[mrsastrakhan]

Aha! Didn't think of that. Our local is pretty low-end, but hopefully they'll have something. I just have about 150-200mi to drive - in driving rain - before it goes in for the service on Thursday and I don't want to risk damaging anything....

 

[plain OM]

The TPMS sensor itself is inside the tire and can't get wet when it rains or when the car goes through a car wash.

Is the TPMS light on steady or is it flashing. This is an important distinction. A steady light means the TPMS has found one, or more, tires seems to have low pressure. A flashing light means that the TPMS system isn't getting a proper signal from one (or more) of the sensors inside the wheels.

which is the nearby gas station. So, I repeat the question: what's the best way to do this using the gas station air pump?

If you want to do it right, there's no "best way" to use the air pump to determine the tire pressure. Most station pumps today do not have gauges, and if they can be set to a particular level, or if there is some sort of gauge on the nozzle, it is most likely very inaccurate.

Are you anywhere near a service station (i.e not a self-service gas outlet) or a tire shop? Most will check your tires for you without charge.

A simple tire pressure gauge is inexpensive, as was mentioned many gas stations (even the self-serve ones) sell some sort of gauge, and they are available at most hardware stores, Wall-Mart, Target, and the list goes on.

 

[Ali_pine]

Sensor is inside the tire - ulikely to get wet/damaged by rain.

Go to station with adjustable air station. Fill the tire to designated pressure. Go to Auto Parts Store and get a 'dial style' tire gage. Go home and check tire pressure after the tires have cooled off overnight.

A couple of pounds above/below specifications isn't going to hurt. SHORT TERM. Get the pressures 'fixed' before taking a long trip.

 

[mrsastrakhan]

THANK YOU plain OM and Ali Pine!!!

Super helpful. Actually, there is a Firestone not far - maybe they can help if I can't get a gauge somewhere quickly and easily. Thank you!!!

It's steady light, btw. Came on immediately after I'd been hacking through what seemed like floodwaters due to this latest monsoon on the east coast, and has just stayed on since. I'm currently letting the tires cool and will then head out to see what I can do. Firestone sounds like my best bet if they'll be helpful

 

[plain OM]

Okay, so there is likely a tire with low pressure. Incidentally, the TPMS doesn't provide a wide margin, certainly not as much as would be required to visually see that a tire is low. I believe that for tires that normally are set at around 32 pounds (per square inch, or "psi") the TPMS system will trigger a warning if the pressure is at 26 psi or below.

It's always possible that you picked up a nail or something similar, and a tire is losing air, albeit slowly.

 

[fatabbot]

Long shot, but maybe prior to the rain your tires were on the borderline of triggering the TPMS light anyways and the drop in tire temp due to water lowered pressure enough to trigger the light.

 

[nhlakes]

17,000 miles through rain, sleet, and snow and the low pressure indicator only came on once. There was a nail in the tire and a slow leak. Indicator did the job.

I agree with the comments about about picking up a digital gauge. Super easy to use. Any auto parts store, bike shops, and lots other places will have them.

 

[OBnube]

4Day Tires and Les Schwab will air up your tires at no charge. I'm sure there are others.

 

[Tom28]

Keep in mind that the reading you get going to the air pump across town (or whatever) will be higher due to the heating of the tire.

You should always check tire pressures when the tire is cold. Which is 2 hours, minimum after driving. And you don't want any sun on the tires in question either.

While getting a pressure gauge, you may want to scope out a nice, small battery powered air pump (should be under $50). That way, you can do everything at home. And you should do it once a month.

Keeping proper inflation not only gets you better gas mileage, but it can have a direct result in how long the tires last, saving you money by not replacing them so often.

 

[mrsastrakhan]

Thanks everybody!

Given the horrible weather, my need to get to work on time, and lack of tools I just had to do the best I could, but the comments here pointed me in the right direction The gas station was a total waste of time (unreadable gauge, and the cheap one I bought from them was broken), but the nice lads at the Firestone nearby took pity on me and helped me out - they not only checked them and filled them for me, but gave me a pressure gauge for future use.

Light switched off after a couple of miles, even though apparently they were only down a very little bit.

All this info is super-helpful, however. I've never had a car this sensitive to tire pressure (first awd car, so a bit of a learning curve). I feel like I know what to do now!! :29: