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      11-27-2012, 04:43 AM   #5

Drives: X3 30d (2011 F25) - now sold
Join Date: Jul 2011
Location: Brisbane, Australia

iTrader: (0)

Originally Posted by cadman50 View Post
that's quite a drop. I would have thought 3-4lbs max and the warning would come on. When the warning is activated, does the nav screen go to the TPMS screen and make one (or more) tires a different color? or do you get a 'ding-ding' sound and a yellow triangle on the screen in front of you?
For me (ie with the indirect TPMS) when the warning is activated, you get the "ding-ding" sound, the yellow warning triangle (or maybe its a big yellow exclamation mark), and the sat nav screen goes to the TPMS screen (I have Prof navigation). The TPMS shows all four tyres (tires) as being flat - colour of tire has changed from green to yellow - ie it doesn't identify which tire is flat. I suspect this is because it is the indirect TPMS and can only detect a relative difference in rotation between wheels - not which tire is at fault. I would have assumed the direct TPMS would indicate the actual flat tire.

I'm not surprised it takes a fair drop in tire pressure before the system alarms. Remember, the system is there to detect a failure of a run-flat tire which would usually mean a near total loss of air pressure. It would be at that point when the run-flat has deflated that you are then under the speed and distance limitations that apply for a deflated run-flat.