Tire heating up...setting off flat tire monitor???

[mug3]

Starting this past weekend, while driving around town, my flat tire monitor ("FTM") lit up. I checked the pressure and all seemed fine, though driver's side rear was a little higher than the other tires. I adjusted the pressure later that day and FTM went on again that night. It has continued to go on several times this week, typically after about 20 minutes of driving.

With a little poking around to see what might be the problem, I noticed that the air pressure in the driver's side rear tire was about 2-3 psi more than the other tires after driving (all were set to 32 psi over the weekend, and still are at 32 in each morning before driving). I also noticed that the driver's side rear tire was noticeably warmer than the other tires to the touch.

I have a 2006 4.8i that I recently purchased (thanks to this board for lots of info and tips), and it has 4 new OEM tires and supposedly a recent wheel alignment (so I am told). There is no material vibration, but a little around 60-70 mph...hard to tell though if the vibration is caused by the road or bad wheel balance.

Does anyone have a diagnosis? I am guessing the rear tire is out of alignment or balance.

Thanks,
mug3

[X5 Meister]

I assume you have an E53 4.8is correct? That being the case, your system is an indirect monitoring system (FTM) reference post # 16
http://www.xoutpost.com/bmw-sav-foru...monitor-2.html

First I'd suggest making sure you are initializing the system properly.

Second, if your car is still under warranty then hit the dealer ASAP.

Third, since your system relies on the ABS speed sensors, it shouldn't go off due to a 2-3 psi pressure change. I believe the change is more on the order of 20% (I have to double check this figure) which would be around 6 psi necessary to trigger it. Have you noticed any issues with the ABS system on your car? Any faults show up, etc.?

Fourth, maybe some experts can chime in who know the system quite well (eg. weasel).