Runflats - on a BMW - Tyre pressure senors ?

[a4drk]

Can someone explain to me how the car knows there's a loss of pressure ?
I thought there was something in the valve

I was driving to Pitlochry on Monday & the back tyre blew out
Turns out I had a nail in it - no warning on the dash
felt the car vibrating, so I stopped & the tyre was flat. Sidewall all ripped in the inside.

The AA man took the wheel off & went & got a replacement tyre
National Tyre in perth SHAFTED me - by trying to say the tyre was £428 !!
I negioated down to £363, but still £60 more than Kwik Fits price.
(It was a Bridgstone RE050A - 255/30/19)
AA guy laughed when he fitted the new tyre & let the jack down - said there was no difference !

I need to get the sensors working now........

David

[BiggestNizzy]

Each wheel has an ABS ring on it to monitor the speed of each wheel.

by comparing wheel speeds it can tell if a tyre is over/under inflated.

[IanD]

I had this with my E92 Touring,mine has the simple dashboard computer.
Once the flat warning is triggered you need to reset it before the warning disappears so hopefully that is all you need to do. Basically you need to go through the menu system find a tyre picture then a reset option. You then need to drive forward a few feet which allows the system to recalibrate itself.

Found out my slow puncture (run-flats ditched previously) was a cracked rear alloy rather than anything to do with tyre