TPMS Valves (Tyre Pressure Monitoring System)

Hintza

I'm looking into buying a couple of new tyres and the car has the TPMS system on it.

I know roughly how it works but just wanted to check what happens when they replace a tyre.

Do you replace the whole valve and is the sensor included in this? Or how does it work?

How much are these valves and or sensors?

maninthestreet

If this is s non-direct TPMS, then there are no sensors in the tyre at all. Presumably, you have a direct TPMS ??

AdrianHi

If you have a system that tells you the actual tyre pressure (direct system) I would hope you can just replace the valve element and keep the original sensor and sender unit.
http://cgi.ebay.com/ebaymotors/09-Chrysler-300C-Tire-Pressure-Monitoring-System-Sensor_W0QQitemZ230441072209QQcmdZViewItemQQimsxZ20100225?IMSfp=TL100225133011r21016

It's not a clear cut question as BMW for example use an indirect system of monitoring wheel rotation speed through the ABS system for the purposes of puncture detection. This is not actual tyre pressure monitoring though it still gets referred to as TPMS. For the USA market BMW supply direct sensors as I understand it is a legal requirement for new vehicles now.

Is there a difference for Europe and USA specification cars in your case?

Hintza

I knew this would be confusing. On the Cherokee as far as I can see it just comes up with the flat tyre warning light so I presume that is the indirect system?

Whilst the old Grand Cherokee had constant reading of all four pressures...is that the direct system?

AdrianHi

Hintza wrote: »

I knew this would be confusing. On the Cherokee as far as I can see it just comes up with the flat tyre warning light so I presume that is the indirect system?

It makes it sound like and indirect system like mine, no sensors, just the ABS system monitoring, then I found this:
http://www.chryslertpms.com/ see chart about half way down, 2007 model year onwards direct measurement pressure sensors
and this:
http://www.ehow.co.uk/how_5270815_reset-monitoring-system-jeep-liberty.html

Jeep being American it seems very likely you have the "direct" system - actual pressure measurement through valve pressure sensors.

It goes on about having to have sensors recoded to the car if you replace them. I cannot see this being neccessary just to change tyres, I expect the valve part you would normally replace at tyre change to be seperate from the sensor.