[Fronzdan]

What do you guys think of this issue? Last night it was probably the coolest weather it's been since I got my '14 335..about 50 degF. Not cold by any means, but the coldest this car has seen. When I started it, I got the low tire pressure warning, but it indicated all four were low. I drove to a gas station with the intent of putting some air in. I reset the TPMS in iDrive and they all show as properly inflated. Haven't seen it today.

Ignore it?

[IndotagSwizz]

Originally Posted by Fronzdan

What do you guys think of this issue? Last night it was probably the coolest weather it's been since I got my '14 335..about 50 degF. Not cold by any means, but the coldest this car has seen. When I started it, I got the low tire pressure warning, but it indicated all four were low. I drove to a gas station with the intent of putting some air in. I reset the TPMS in iDrive and they all show as properly inflated. Haven't seen it today.

Ignore it?

I'm confused, so you did the idrive reset without checking whether the tires had the right pressure?

[Hernandiaz11]

Cold temperatures will make the pressure within the tire decrease because the air behaves according to the ideal gas law. PV=nRT

The temperature (and the air pressure) went down low enough to trigger the low pressure warning threshold; however, the tires warmed up due to friction while driving thus increasing the air pressure to acceptable values.

[Fronzdan]

This is what I assumed. But it was just weird since it wasn't THAT cold. I can probably expect them to fire again when the temps drop then. I'll put some air in then

[Fronzdan]

Originally Posted by IndotagSwizz

I'm confused, so you did the idrive reset without checking whether the tires had the right pressure?

I didn't check the pressure with a gauge since I didn't have one. I did get out in the parking lot to eyeball them and they weren't running flat or low. I went to the vehicle status page in IDrive and it showed all four as being low. I drove about a mile to the gas station, filled up the tank and was about to pay the buck to fire up the air compressor. But I did a reset and they all showed up in spec

[Orion4]

All you did when you reset the TPMS was set the current tire pressure values has the new baseline. Get a guage and set the pressure that you want and then reset the TPMS.

As a baseline, Tire pressure changes 1-2 psi per 10 degrees of temp change.

[Fronzdan]

Ohhh! I assumed the reset just cleared the error and took another reading against a programmed value. (A classic RTFM moment I guess) Looks like I'm picking up a gauge and resetting the system correctly.

Thanks for the help!

[Orion4]

No problem. Glad to help.

What is really annoying about the TPMS display is that it only shows which tire/tires are low when the actual tire pressure and tire temp information is in the system. you have to have someone modify the coding to display actuals. Don't know why BMW did it that way, at least in the US

[Fronzdan]

Originally Posted by Orion4

No problem. Glad to help.

What is really annoying about the TPMS display is that it only shows which tire/tires are low when the actual tire pressure and tire temp information is in the system. you have to have someone modify the coding to display actuals. Don't know why BMW did it that way, at least in the US

No way. That would be a useful system. The way I thought it worked would be nice too. You enter the desired pressure for each tire in iDrive. Then the system measures and monitors based against that. Then no need to even use a gauge.

So I did a real reset this time. They were all low.