[Katrin Knauer Mellody]

Hi Everyone,

So the little Low Tire Pressure Warning icon came on for the first time a few months ago, when we got the first cold spell; at that time, I took it to the dealership and they told me it had to do with the temperatures dropping and was nothing to worry about. Ok, fair enough. I guess they turned it off.

Then a few weeks ago, when it got REALLY cold, it came on again, so we checked the pressure and it was slightly low in some tires, so we added some air - but the warning stayed on! So I checked the pressure again (was wasn't easy to do since pretty much ALL air thingies at the gas stations were out of order!!) but when I finally found one that worked, it said that all the tires were fine...Oh well, I thought, maybe it's just because of the cold so ignored it.
However, it is now 60 degrees here and the warning light is STILL on??? WTH ?? Does anyone know what this is all about? How can I get it to turn off?

Thanks for your help/advice!

Kat

 

[Steve Frank]

Hi Kat, I had the same issues with my 2018 GT when I first got it. First, keep the car in the garage so the tires settle down temperature wise. Fill them up so they at the correct pressure settings. Then follow the instructions in this video to reset the TPM, it will use the current pressure as a calibrated starting point when you do this, so be sure to have the tires set at the right pressure before you do it.

If you don't have a way of putting air in the tires with them "settled down" you can still do this of course.

My old Mazda 3 always lost pressure in sub-zero temps as well. Didn't matter if the tires were OEM or oversized, those rims always leaked. I kinda expect the same from my newer CX-3.

- Steve

 

[NotAPreppie]

The TPMS in the CX-3 is based off of the ABS system. It watches the wheel speed sensors to see if any of the wheels are turning slightly faster or slower than the others.

When you reset the system, you are telling the system "the pressures are correct, remember these relative rotation rates."

I think the standard for detection is 20% in 20 minutes (or pretty close to that). That is, the system has to warn the driver within 20 minutes if one tire changes by more than 20%.

The annoying side effect of this is that if you drive one tire over a bump under power, and that wheel bounces off the ground, it will spin a bit faster than the rest until it comes back down. Since the system knows that the brake isn't applied, it thinks that one of the tires has gone flat. (Edit: This is just a theory but it would explain why people get TPMS warnings after going over bumps.)

Another side effect of this is the gas laws. Pressures will change roughly 1 psi for every 10F. However, as long as all the tires change at the same rate, the system probably won't know because all of the tires should still have roughly the same rotation speed relative to each other.

If you've reset the TPMS and you're still getting warnings, it's possible that one or more of a few things have happened:

Quit flooring the gas over bumps... (j/k)

There's a problem with one of the tires that nobody has found yet.

User error. I trust you can follow directions but maybe you made a mistake.

Last, I read on here somewhere (but can't find it anymore) that if you try to reset the TPMS more than 2 or 3 times in a single drive, it will assume a system malfunction and only the dealer can reset it after that.

I recommend you get a $10-$20 dial-type tire pressure gauge and leave it in the glove box. I hate the stick type and never trust the ones at the gas stations.

 

[Katrin Knauer Mellody]

Hey great info, thanks!!
I'll get a tire pressure gauge, that's a great idea (I think we may actually have one, but I have no idea where and how good it is. Probably not great...)

So I haven't tried resetting the TP...whatchamaycall it yet. I didn't know I could do this - I thought the light was supposed to turn itself off or the dealership would have to do it. I'll watch the Youtube video, but first I guess I will check the tire pressure yet again...

Will keep everyone posted!

Kat

 

[Katrin Knauer Mellody]

Wait - so there is one simple button somewhere??? The car in the video looks very different from mine, where is it in the CX=3??

 

[anchorman]

Wait - so there is one simple button somewhere??? The car in the video looks very different from mine, where is it in the CX=3??

Down on that little panel near your knee. Press and hold it until it beeps but ONLY after you make sure the tire pressures are OK. If you keep resetting it, it will assume you are attempting to ignore a soft tire and lock you out so only ever do it once after checking the tires.

 

[Katrin Knauer Mellody]

Great advice, thanks!
Do you perchance have a recommendation for a good home tire pressure gauge and inflator? I know nothing about these things, but I do know it's a pain going to the gas station machines so would like to have a good one at home!

Also, how often would you recommend rotating the tires? We've had the car about 6 months now, does it need to be done? Would the dealership do this for free?

 

[Brigitte]

Down on that little panel near your knee. Press and hold it until it beeps but ONLY after you make sure the tire pressures are OK. If you keep resetting it, it will assume you are attempting to ignore a soft tire and lock you out so only ever do it once after checking the tires.

Yep, I had my TPMS triggered when going over some rough roads in the fall. Checked all the pressures, everything was fine. Did the reset and it hasn't come back on since.

 

[Indydriver]

If you own a car, you should also own a quality pressure gauge AND a small compressor. When buying tools of any kind, it pays to buy quality. Here’s the best pressure gauge I’ve ever owned. It’s analog (preferred) with a handy bleeder valve. So the fill procedure is to over fill the tire on the first pass, then bleed the pressure down to EXACTLY the pressure you want. Saves time from back and forth with gauge and air filling and gets a nice accurate fill every time. For a garage compressor, I recommend the Porter-Cable 6 gal “pancake” compressor at $99 as found at Home Depot. Ladies, these make wonderful birthday, Fathers Day, Christmas or even Valentine’s Day gifts for boyfriend/ Hubby. These are must haves for anyone’s garage.

https://www.tirerack.com/accessories/detail.jsp?ID=166

https://www.homedepot.com/p/Porter-Cable-6-Gal-150-PSI-Portable-Electric-Pancake-Air-Compressor-C2002/203162815

 

[Brigitte]

Ladies, these make wonderful birthday, Fathers Day, Christmas or even Valentine’s Day gifts for boyfriend/ Hubby. These are must haves for anyone’s garage.

They also make great gifts for women who care about their cars.

 

[Indydriver]

LOL, G.I. Jane, eh?

Around here, any guy who got his GF an air compressor for V-Day would be buying his last gift for her.

 

[NotAPreppie]

I used this gauge when racing (until it got run over by somebody that looks suspiciously like me driving a car suspiciously similar to mine... oops).
https://www.amazon.com/Longacre-50417-0-60-Pressure-Gauge/dp/B00DL6T2YK/

Any $20-$30 tire inflater off Amazon will be roughly the same.

 

[Katrin Knauer Mellody]

Maybe you have the wrong girlfriend(s) I'd much rather get something like this than a bunch of wilting flowers LOL.
But you're talking to the woman who didn't want wedding rings, either!

Thanks for the advice - I ordered something off Amazon yesterday, just a small thing that I can keep in the car. See how that works - I can always get a bigger one after that to keep in the garage.

 

[Brigitte]

LOL, G.I. Jane, eh?

Around here, any guy who got his GF an air compressor for V-Day would be buying his last gift for her.

Having a uterus and caring about my vehicles does not make me G.I. Jane.

On my last car, I got new brakes (rotors and pads all around) for my birthday. Installed by him. He's also off the hook for Valentine's Day (a stupid occasion, in my opinion). Because of that, I have fresh flowers in my house, all year long, for no reason at all. From him.

Thanks for the tips.

 

[Katrin Knauer Mellody]

[QUOTEHe's also off the hook for Valentine's Day (a stupid occasion, in my opinion).[/QUOTE]

I couldn't agree more!! I don't need someone telling when my hubby and I are supposed to express our love for each other (and spend lots of money on stupid stuff in the process!!)

Alas, I can't really have most flowers in the house because we have four cats :laugh:

 

[stephenk43]

The upside to the CX-3 TPMS system is that after years of use there are no batteries to go bad(and need expensive replacement of sensors). The downside - if all tires lose pressure at the same rate, no warning will be shown. Pressure should be checked weekly. Its rotational difference that triggers. Here in WV we have 50 degree changes in a week. There is roughly a one pound change in tire pressure for each 10 degree temp change. If you are tripping after a major temp change, tires should be adjusted accordingly before traveling. After adding/dropping air pressure reset TPMS per manuel.

 

[mainemanx]

Once again, speaking from the old school, TPMS strikes me as much ado about very little ... more a PC, feel-good palliative than actually reducing fuel consumption.

Both the wife's HR-V and the CX-3 use ABS-based systems. Interestingly, while we've never had a false alarm with the HR-V, the CX-3 has had several (approx. 7K miles each).

The major advantage to our ABS-based system? Fitting snow tires on a set of winter rims, you can laugh at the dealer trying to charge you an extra $200 for individual wheel TPMS sensor/transmitters!

 

[NotAPreppie]

IMO, it's less about fuel consumption and more about not having a repeat of the Ford Exploder/Firestone debacle. The fuel consumption thing is mostly icing on the cake.

https://en.wikipedia.org/wiki/Tire-pressure_monitoring_system#Firestone_recall_and_legal_mandates

 

[Katrin Knauer Mellody]

Seriously, once a week?Does anyone really check their tire pressure once a week?

 

[Katrin Knauer Mellody]

Once again, speaking from the old school, TPMS strikes me as much ado about very little ... more a PC, feel-good palliative than actually reducing fuel consumption.

Both the wife's HR-V and the CX-3 use ABS-based systems. Interestingly, while we've never had a false alarm with the HR-V, the CX-3 has had several (approx. 7K miles each).

The major advantage to our ABS-based system? Fitting snow tires on a set of winter rims, you can laugh at the dealer trying to charge you an extra $200 for individual wheel TPMS sensor/transmitters!

The HR-V was our closest competitor!! We really liked that one, too. How do you guys like it? How does it compare to the CX-3?