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Baby It's Cold Outside

5K views 30 replies 16 participants last post by  smarties 
#1 ·
Every time the temp falls below 40 degrees (which is obviously happening more and more, and will happen probably every day beginning in January), my tire sensor warning light comes on in the morning. At first it freaked me out, and I would manically check the air pressure, put air in to make sure everything was just right, etc. But after doing that 2 or 3 times I realized ... duh ... the pressure is low because of the cold. Sure enough, after 3 - 4 minutes of driving, I could simply reset the sensor light and everything was fine.

So, here are my questions:

(1) Anyone else having this issue?
(2) Is there a way to set the sensors so that they don't freak out every morning?
(3) Should I care about this, or should I just consider it yet another "oddity" (like the "always on" radio) of my Smart.
 
#3 ·
As the temperature continues to drop, I find that I need to add air almost weekly to compensate for the drop in tire pressure. Check tires in the morning when they are cold and out of the sun. If you add air, be sure to reset the button on the dash. This should solve your problem.:)
 
#5 ·
Thats crazy

I wonder if thats what they do in France and Canada where it is really cold already? Makes :cool:me wonder if I should have ordered sensors on mine?
Is yours a 2008 or older too?
Se




me out, and I would manically check the air pressure, put air in to make sure everything was just right, etc. But after doing that 2 or 3 times I realized ... duh ... the pressure is low because of the cold. Sure enough, after 3 - 4 minutes of driving, I could simply reset the sensor light and everything was fine.

So, here are my questions:

(1) Anyone else having this issue?
(2) Is there a way to set the sensors so that they don't freak out every morning?
(3) Should I care about this, or should I just consider it yet another "oddity" (like the "always on" radio) of my Smart.[/quote]
 
#7 ·
The volume of air in these tires is a bit less than most folks are accustomed to. You may notice that it takes less time to add a pound or two to the smart tires and it does on a larger vehicle.
That low volume tends to make them a little more susceptible to pressure vaiations due to temperaturere.
If you adjust your tire pressure when the tires are cold (before driving one mile), and reset your TPMS system, you should be good until the temperature drops significantly.
I personally don't buy into the nitrogen thing, but maybe using nitrogen will keep those pressures more stable as the temperature drops.

. . . or maybe I'm just full of it! :)
 
#10 ·
ShoshTrvls, TPMS warnings aren't specific only to smarts. We travel with, test and market all sorts of different cars all over the country (and Canada) and it's a fairly common thing to see when the weather first turns cold, especially if the tires are right at or a few pounds below recommended pressures to begin with. Just air them up to recommended pressures (see door jamb label) when they're completely cold and your TPMS warnings should disappear.

Cheers,
Arch

PS, Nitrogen is a complete waste of money.
 
#16 ·
FWIW, I've been noticing this phenomena for the past 7-10 days. While I live in north Florida, and it hasn't been THAT cold yet. Our lowest temperatures have been in the 50s. I'm going to follow the suggestions to air up first thing in the morning, when the tires & temps are lowest.

I'm glad this topic was brought up. I was getting a little concerned, but I figured it was probably temperature related and just haven't gotten around to adjusting the pressure yet. The indicator light goes out after a few miles of driving for me too.
 
#17 ·
NCC1701..can you do a quick experiment for us...
check the tire pressure early in the morning before fill up and then again late in your sunny/warm/beautiful FL afternoon? (damn..I hate you) j/k...and see what the difference or gain in pressure is...I'll do it here but we are in cold weather already and the change from morning to afternoon is not that much.....

jetfuel
 
#19 ·
NCC1701..can you do a quick experiment for us...
check the tire pressure early in the morning before fill up and then again late in your sunny/warm/beautiful FL afternoon?
jetfuel
I'll endeavor to do that tomorrow and take notes of the measurements.

About your impression of my weather, I wish you could take it. I hate having HOT, MUGGY weather for 7 to 9 months of the year. THIS is my favorite time of year in this part of the country....
Tonight
Partly cloudy becoming mostly cloudy after midnight. Lows 47 to 52 :). Northeast winds 5 to 10 mph.

Wednesday
Mostly cloudy with a 20 percent chance of afternoon showers. Highs 70 to 75. East winds around 10 mph with higher gusts near the coast.

This is North Florida, not Miami.
 
#21 ·
Thanks for everyone's thoughts/confirmation.

I would do the test as well, but I really have no interest in climbing under the dash to take out the tire inflator first thing in the a.m., hooking it all up, juicing up the tires, and then putting it away -- in sub-freezing temps. But when the cold really sets in here, I'll go to the local gas station and slightly overinflate my tires and see if that helps.
 
#23 ·
I adjusted tire pressure last week, temp was mid 70's. Monday it was 20 degrees and tire pressure dropped 3 PSI which I guess is enough to set off the sensors. Tuesday it was snowing and raining. Tire pressure stayed the same but this light came on, it was a triangle with an excamation point in it. I was going across a bridge that had snow and ice on it. Guess I shouldn't have hit the gas so hard. I also tried out the brakes. stopped nice and straight.
 
#24 · (Edited)
jetfuel:
At 55°-At 78°
RR 28 - 29.5
RF 22 - 23.0
LF 21 - 23.0
LR 28 - 30.0
Car had been resting a minimum of four hours previous to each check.
Aired up immediately. Obviously, I need to check more often. And, pay attention when the car tells me they're low!

EDIT: At the second check, the temperature was on the rise, so likely the tires' air hadn't yet reached 78°. A couple more unknowns: Location of the car's temperature sensor, where I got the temperature reading from. First thing in the morning the ground is often substantially colder than the air just a few feet above it. And, just how accurate is my pressure gauge? I trust it more than I do the gauge on my el-cheapo compressor, which appears to read 3-4 pounds too low.
 
#26 ·
Same as Vette

Tire pressure sensors can be sensitive to the cold and if your on the mark at 70 degrees it's likely your sensor will come on at 40 degrees. The Vette actually reads the pressure in each wheel and it will gain 4 PSI between the morning startup and the drive home. You gotta love technology :)

26.2
 
#30 ·
Thanks NCC...so..an average of 1.6...
It seems to me that the tires are under inflated by a few pounds ,if we go by the tag on the door jam....cold tire press front 29 rear 36 . with standard size tire...
and a maximum of 44 as stated on the tire wall...
humm. got an idea...to test the sensor..bleed air out little at a time until light comes on, read pressure at that time ..do it to all tires and see how close the sensors are to each other...and then re-fill with N2....you knew it was coming..LOL
I'll post results later

jetfuel


jetfuel
 
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