TPMS annoyance in the cold weather

I live in SE Pennsylvania near Philadelphia, and the NE corridor has had a good dose of winter this past week. I notice when the temperature drops below 25, the TPMS starts acting up. Pretty much every day last week on a cold start, it was telling me all four tires were low. After about 10 minutes of driving, I would reset the system (actually went as far as to map the reset TPMS to preset #6) and the alert would clear itself. Anyone else experience this issue during this most recent cold spell, and as frequently? (Literally 100% of the time on cold start when temp is under 20)

On another note, the heated steering wheel has been awesome this past week. While I still would rather have the M wheel, the non M wheel has its benefits.

Yes, I'm in PA too. This is not unique to BMW. Very cold weather wreaks havoc with TPMS on all cars.

I don't understand the physics behind it,but it's really a pain.

I saw this on my e90 and my Acura TL.

My neighbor says he has the same problem with his Mercedes.

EDIT: fixed spelling mistake.

Have you checked the cold pressure of your tires? They may well be low for the ambient temperature.

We recently had a bought of -15 and I had no issue with TPMS.

Maybe they are low? Have you verified they aren't with a TPG?

http://www.bimmerfest.com/forums/sho...9&postcount=14

When I experienced this, tire pressure was fine. As soon as the temp goes above 30, the TPMS warning doesn't come back on.

I've seen this on my e90, my TL, and again, my neighbor was telling me he has the same issue with his Mercedes. As soon as it gets warm, the TPMS warnings go away.

It is sort of strange though that some people don't see this.

I just did a search on google.

Apparently this comes up in virtually every single car forum out there. Honda, Chevy, Dodge, etc.

Some people say that you need more air in the winter time. This makes sense I suppose.

But people report the same basic thing, the TPMS warning comes on, as soon as the car heats up, the warning goes off...This is exactly what I see.

http://www.tpmsmadesimple.com/faq.php

What do I do when my TPMS light comes on during cold weather?
Does this really mean my tires are low? Any time that the TPMS warning light comes ON, there is a possible low tire pressure condition. Tire pressure can drop due to cold conditions, and this drop in pressure may cause the TPMS light to come ON. As the tire warms up under normal driving conditions, the light may turn OFF. If the cold weather conditions cause the TPMS light to stay ON, check the tire pressure (when tires are cold) and inflate the tire to the proper pressure indicated on the door placard.

And it could very well be that the air pressure in the tire when cold is below the allowable threshold, thus the warning.

I had this issue on my E92 on the first real cold morning, light came on for one tire. The tire was 2 psi under. Added air to be safe, reset the TPMS, hopefully that'll be the last of it for the winter.

cold weather drops tire pressure....which is what sets off the monitoring system.

ideal gas law (for our purposes, we can apply this to mix of gases in air)

Pressure = (number of moles of gas x universal gas constant x temperature)/ volume

for our scenario, the only variable changing is the temp. in order to increase the pressure, we need to increase the number of moles of gas, or, simply put, pump more air in. the tire pressure alert will shut off when the tire warms up as well, but will be underinflated when cold.

(this law applies to "pure" nitrogen tire fill)

as for why it doesnt affect some people-- depends on where the setpoint was and what the temperature was at that time. setting the tire pressure in cooler weather (say fall or spring) would be less likely to trigger a cold weather drop than setting it in the summer. but regardless, the tire pressure does drop when cold

Tire pressure drops 1 psi for each 10 degree drop in ambient temperature, in addition to losing 1 psi/month.

Add more air for the winter.

The TPMS warning goes out as one drives as the tire pressure increases as the tires warm. This is not resolving the issue however. See above.

Originally Posted by Orient330iNYC

cold weather drops tire pressure....which is what sets off the monitoring system.

ideal gas law (for our purposes, we can apply this to mix of gases in air)

Pressure = (number of moles of gas x universal gas constant x temperature)/ volume

for our scenario, the only variable changing is the temp. in order to increase the pressure, we need to increase the number of moles of gas, or, simply put, pump more air in. the tire pressure alert will shut off when the tire warms up as well, but will be underinflated when cold.

(this law applies to "pure" nitrogen tire fill)

as for why it doesnt affect some people-- depends on where the setpoint was and what the temperature was at that time. setting the tire pressure in cooler weather (say fall or spring) would be less likely to trigger a cold weather drop than setting it in the summer. but regardless, the tire pressure does drop when cold

Put more air in your tires when it gets really cold.

Stop by your friendly Costco and ask them to put a couple of lbs extra into each tire...they will do it free of charge. If the light won't go out. reset the TPMS. That's what I had to do with my Lexus.

BTW - Costco uses nitrogen which it's my understanding it's molecules are larger and don't leak out of tires as soon as regular air. Reason why it's used in racing cars. I don't have scientific proof about this...

Originally Posted by HugH

Stop by your friendly Costco and ask them to put a couple of lbs extra into each tire...they will do it free of charge. If the light won't go out. reset the TPMS. That's what I had to do with my Lexus.

BTW - Costco uses nitrogen which it's my understanding it's molecules are larger and don't leak out of tires as soon as regular air. Reason why it's used in racing cars. I don't have scientific proof about this...

regular air is 78% nitrogen.

BMW has an SIB about nitrogen...

SI B 36 04 06
Wheels and TiresApril 2006
Technical Service
SUBJECT
Nitrogen Inflated Tires


MODEL
All


SITUATION
Many customers have inquired about the use of Nitrogen, instead of air, to inflate tires on their BMW vehicles. Please review the information below to help answer some of the customer's inquiries.

INFORMATION
Nitrogen, an inert gas, is nothing more than dry air with the Oxygen removed. The majority of "air" already consists of Nitrogen (78% by volume). The other elements of air by volume are 21% Oxygen and 1% other gases.
All BMW approved tires have been designed and tested to deliver their expected performance when inflated with "air" and the correct tire inflation pressure is maintained on a regular basis.
The use of Nitrogen to inflate tires is not recommended for normal use of BMW vehicles; however, the use of Nitrogen is also not prohibited.
There are certain applications where Nitrogen inflation is advisable, i.e. in abnormal environment where wheel and tire overheating may occur such as in aircrafts, space shuttles, military vehicles, off-road trucks, and race cars. In these applications, the non-flammable Nitrogen can reduce the risk of fire, because Nitrogen does not support combustion and does not add fuel to the fire.
The physical properties of Nitrogen may reduce the inflation pressure loss only from the tire material natural permeability (diffusion through rubber). However, similar to air, Nitrogen can still escape from other sources of inflation pressure loss such as from wheel, wheel/tire interface, valve, and valve/wheel interface.
The most important thing for the customers is to maintain the correct tire inflation pressure on a regular basis as recommended in the Owner's Manual. Under inflated tires can reduce road holding, increase hydroplaning risk, increase road hazards sensitivity, reduce tire life, increase fuel consumption, etc.
If equipped on the vehicle, always reinitialize the Flat Tire Monitor (FTM) or reset the Tire Pressure Monitor (TPM) after the tire inflation pressure has been corrected.

A nitrogen fill escapes from tires as readily as "air." The major reason a nitrogen fill expands more and contracts less is all moisture is removed as part of the extraction process. Air containing moisture vapor expands and contracts much more than a dry gas without moisture.

Naturally, using exclusively BMW approved air avoids all of these issues.

Interesting on the SIB from BMW not recommending nitrogen. I recall several years back that one of the BMW dealers had sent out as part of their coupon mailing advertising their using nitrogen to inflate tires. This was most likely before the SIB was issued.

The SIB is agnostic: N2 is neither recommended nor prohibited; i.e., do whatever you prefer.

My Lexus dealer charges $60 bucks for a N2 refill. Of course, I never went for it!

Originally Posted by HugH

My Lexus dealer charges $60 bucks for a N2 refill. Of course, I never went for it!

Lol, just go to Costco and get it for free.