I have a 2003 Mini Cooper...Last night I noticed that my front left tire was low...This morning I checked it and the psi was like 10 and I had to fill the tire up with my portable air tank and took it to a near by tire place. They said that I have a slow leak somewhere in the tire....I didn't have time to have them take a look at it because I had to go to my college class. Anyways I was wondering why the flat tire warning light didn't come on? Anyone have any clue why?

Thanks

 

What's the pressure on the other tires? I've found there needs to be at least a 10-15# difference between opposite tires for the warning light to illuminate.

 

On gen1 cars, the car is looking for a change in total tire rotations per mile...if one suddenly changes...like from going flat...more rev's per mile...the warning will light up. Since the system is not super-accurate, and it was only desgined to let you know that you are driving on a flat runflat...it does not respond rapidly...
On gen2 cars, and very late gen1 cabrio's ( I think), the in rim tpms monitors actual air preasure...and will set off a warning if the preasure vary a small amount....stop br the dealers on the first cold day...you will see a bunch of gen2 owners complaining about tpms issues...and getting a psi or two of free air!!