Fellow CM owners.... Today in Vermont, super cold 3 degrees F . Car starts up great, but as soon as I pull out of driveway, warning light comes on - all 4 tires "low" graphic comes on in driver info display. Plus yellow warning ! in the main dash. Checked manual, have all weather run flats. Car running fine, tires look normal

Is this expected/ok?

 

It means that you have low tire pressure. Run flats have very thick sidewalls, you CANNOT tell if they need air by looking at them. Get your tire pressure gauge out and check them. Once you have brought all four tires to the correct pressure level, read your manual on how to reset the TPMS system.

 

I have an '11 base cooper, and my tire pressure monitor came on saying that my front left was low. I'm in North New Jersey, so I figured it was due to the drop in temps as well. The tire did look a little low, so I went to the gas station and put air in, looks fuller now, but it's still saying it's low. I'm taking it to the dealer this week, these cars have awful computer bugs that come out when the temps get low.

 

Eddy, it isn't a bug, you MUST reset the TPMS after filling your tire. Read the manual on how to do this. The only way to accurately tell your tire pressure is to use a tire gauge, visually CANNOT tell if the tire pressure is correct.

 

Yea, i would check the tire pressures and if it isnt that follow the manual to reset the sensors. i may fix itself.

 

Ok, thanks, I didn't know it was necessary to reset the tire pressure monitor, I figured it'd just go off once enough air was detected in the tires. It had happened once before, same tire I think actually, and once I put air in it, the warning light went away, so I just assumed it would do the same thing this time. For my tires, it says 33psi is needed, so that's what I set the air machine to so I figured it should be fine now as far as enough air goes, but I don't know how accurate the machine is. I have a manual gauge somewhere, I'll have to find it.

 

All 4 tires have to be the exact same pressure (33). The TPMS will detect if any of them is just a bit off. I have had this happen mostly during cold weather when one of the cars hasn't been out in awhile. But it also happened with my CUBE when I was at a Greyhound silent auction. All was fine on the long drive out, but about a mile down the road on the way home (cold night) the monitor came on.
I carry a great racing tire gauge that was my husband's. It is worth every penny. I got the car home after checking and finding that one tire was one pound off. Luckily I have an industrial-sized compressor so I fixed it at home.
When Rich bought that thing I wondered why he would need it. Now I love it, saves trips to the tire places.
I wish the MINI would reset as easily as the CUBE, but after you've done it a couple of times it isn't a big deal.

 

That should not be so...most cars need different front to back pressures depending on weight distribution of the car and its cargo.
There is usually a sticker on one of the door jambs indicating recommended front & back tire pressures for typical loads and also depending on wheel sizes.
Once the pressures are correct (must use a reliable guage) then you reset the pressure monitor system and it just detects any significant change from that point in each tire.
Canadian cars don't monitor pressures directly...instead each wheel's rotation rate is monitored via the ABS system to deduce a low pressure tire (since it will rotate faster as its effective diameter decreases).

 

UPDATE: Many thanks to CM owner rhawth99 for his sound advice....followed owners manual instructions, checked tire pressure with accurate guage, all 4 tires were approx 24 PSI instead of 32/33 as recommended. Guess the bitter cold (and the laws of physics) impacted the PSI level. Filled up the tires to proper PSI, re-checked with tire gauge - all good. Then followed instructions to re-set system via owners manual - easy. Drove more than 300 miles around Vermont and back to NYC with no incident.

Moral of the story - definitely don't panic, read the manual, check in with the NAM forum for advice and count yourself lucky we have quirky smart cars.

Thanks again for the support

 

Hey Ddmnyc. Those same laws of physics will kick in when the temps warm up a little. Once (if) the cold snap ends I'd suggest rechecking the tires to make sure you aren't then running too far above recommended pressure. In some cars handling gets a bit twitchy with too much tire pressure

 

Agree. The introduction of active tire pressure monitoring to the new car buying public in the US is going to have an interesting educational effect. People are definitely going to get a better understanding of the effects of the Perfect Gas Law.

 

.. or we'll all end up putting nitrogen in rather than 'air'. Less water and less temperature-dependent variability compared to the standard atmospheric top-off.