i have an e60 530d sport with the run flat 18s as standard fitment.

today i put on a set of 172's, they are original wheels, i do not know if they have any sensors inside for monitoring tyre pressure. anyway, i put them on and the system showed under rpa that status is ACTIVE and i drove for about 2 miles then the red warning light came on that i have a puncture. I looked into the manual and read that you should reset the system if you put air in or change a wheel etc.... the system then reads intialising and has not changed so far. the maunual says it will complete this process in due course. i want to ask do my wheels need some kind of sensors inside or does this system work without sensors?? any help much appreciated.

 

You may need to drive for several miles before the system will become 'Active'.
Check the tyre pressures then set the system to initialise itself and drive. I have found that the less turning you do ie a 'straight' bit of road the quicker it will reset itself.
The system requires a measurement of the number of rotations the wheels give based on inputs from the ABS system over a set distance.
A wheel with a flat tyre will have to rotate more times over a given distance than a fully inflated one.
The later cars have individual wheel sensors and will show which wheel is showing low pressure as opposed to a blanket flat tyre warning.

 

thanks daven, you were right, i took it out for a longer drive and it switched to active. problem sorted! thanks

looking nice on the 172's glistening in the lovely sunshine we have today!!