TPMs reset requiring magnet, why?

[MKhan01]

Hello everyone,

Curious to know why a magnet is required when resetting certain TPM systems. Somewhere I read it is to make the signal stronger and to notify the receiver of which wheel you are programming, another statement I read was there's a reed switch inside the sensor and the magnet closes it.

Any definitive answers?
Any definitive books on TPM systems?

Thanks everyone

 

[NormPeterson]

Might find something poking around over at Bartecusa.com .


Norm

 

[MKhan01]

Hi NormPeterson,

I checked Bartec, but no detailed info. I am under the assumption that to get to the basics of this I would need to consult a RF signals textbook or something similar as the manufacturers service manuals are tremendously vague.

 

[LionelHutz]

It's just used to activate the sensor so it transmits a pressure signal. The vehicle tyically has a programming sequence on the sensor setups that require a magnet to program. So, as you put the magnet to each sensor it activates and transmits an ID signal so the vehicle can acknowledge the sensor ID for each wheel in the sequence as you work around the vehicle. I would suspect it's a type of reed switch. It needs to close when the wheel is rotating and the magnet has to be able to close it as well.