After leaving my car parked for about 3 hours in 28 degree Celsius (no snow) conditions, my MY2008 gave me a "low tire pressure" warning as I was leaving the parking lot. I checked my tire pressure (cold tires) and all four were all at 26.5 to 27.0 PSI. I am running the stock RE050s. I don't know if this is significant, but today was also the first sub freezing day of the year, and the first time that my car has been subjected to below freezing temps. Is the TPMS system know to be affected by cold conditions? Should I be worried about a bad sensor? The manual repeatedly states that the system will only go off if the tire pressure is SIGNIFICANTLY below recommended levels. Is 26.5 PSI cold way too low (manual says 32 PSI cold)?

Thanks for the help!

 

Pretty sure that could be counted as significant... definitely significant enough to affect the car's handling if only one of the tires was at that level and the rest were at 32. I don't think its a bad sensor at all, I think you just need to fill your tires with air .

 

The TPMS triggers if the tires are at near or below 25% of the recommended pressure, at least for most cars. Most likely what happened is that before the cold snap your tires were already near the threshold and after parking it at low temp the pressure decreased even further. Just check your air pressure and you're good to go

 

That's low enough to turn on the light.

 

oldskooleskimo Posted on Dec 4 2009, 07:16 AM
I've never seen snow outdoors in 28° Celsius.
Ever!

In Dubai you can actually ski indoors with outdoors temps of 40°C and up.
But that is off-topic.
http://www.skidxb.com/English/faqs_eng.htm?mid=2&sid=11

 

The Lexus does the same thing except it doesn't need 25% below the recommended pressure, it only needs 1 psi drop.

It's aggravating, but you ignore it at your own peril. The stock car uses such low profile tires that you can't really tell if it's lower than that by the driving feel. In the S low tire pressures will make the car pull but on the lower profile Lexus tires it doesn't and I've already ruined one tire because the light stayed on all the time so I ignored it. Recommended pressure is 32 but at 31 the light comes on.

 

TPMS are one of the more aggrevating modern day safety features.

Personally, since the S2000 is sensitive to variance in tire pressure, you should still manually check them periodically. I don't trust the TPMS at all, because as you've discovered...climate affects the reading.

Not sure if it works in the S2000 (mine is '03 w/o TPMS), but I removed the TPMS sensors out of my 350Z wheels and the dash light does not illuminate. Maybe someone with an S has done this and can validate if it works.

 

Yes 26.5 PSI is too low and triggered your TPMS. I'm not sure if what kind of TPMS does newer S200 has, but if its a loop system or something it wil affect driving characterestic of the car.

 

If the manual suggests 32psi, why did you let your tires drop to 26.5-27psi?

 

Since your in very cold climate you might consider running your tires at 30lbs versus the suggested 32. On warmer days in your area the tire pressures will increase slightly. This is just a compromise though, but it could be a little safer than trying to maintain the full 32lbs of pressure.