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[likkuid_22]

I read at couple of places that the Canadian version of the 128i has the TPMS sensors on the ABS system. is this true? I plan on buying the A7 wheels from tirerack, therefore I guess I do not need to buy the TPMS sensors? Can anyone confirm?

Thanks

[Lester]

No Canadian cars are equipped with TPMS - we get FTMS which guesses at tire pressure based on revoutions per minute differences so no - you don't need them.

[magha]

they are all equipped with TPMS but some of them have it running through drag sensors in the brakes.You can tell by the valve stems on your stock wheels. If they are rubber than its built into the brakes.

[aerobod]

Originally Posted by magha

they are all equipped with TPMS but some of them have it running through drag sensors in the brakes.You can tell by the valve stems on your stock wheels. If they are rubber than its built into the brakes.

I'm not sure what you mean by "drag sensors", but the FTM system used on Canadian and other non-US cars doesn't use any additional sensors than the car already has. The ABS / DSC wheel pulse sensor at each wheel provides a signal to various systems, including the FTM system. It is then a matter of software, a reset button and a warning light to complete the FTM system.

All the software is doing is counting the number of wheels pulses at each wheel when the car is going straight (probably determined from the steering sensor that is also used in the DSC system). When any wheel shows a different number of pulses outside of a given tolerance limit over a given distance for it's calibrated setting relative to each other wheels calibrated setting, then the warning light for the FTM will illuminate showing a tyre pressure problem. If the tyres are a different size from each other, the reset procedure will re-calibrate the system to take into account a different number of pulses for a given distance for each wheel. With this type of system, pressure changes due to temperature will not trigger the system if all tyres heat and cool to the same temperature.