Strange !! I rang the dealer for prices and after I gave them the reg number they say my car has none listed for it ???? Looking at the stem on the valve they do look like normal valves ?? Confused as I have the tyre pressure loss thing on the display ?
The gizmos wot do the telemetry are inside the wheel - long oblong things that the valve screws into. You will know the valve is a TPMS one as it will have a hex nut at the base of the valve. Post a photo of the valve and someone will tell you.
It was my understanding that all 172s had individual TPMS (The Brabus catalogue also thinks this is the case for EU cars). Does your display show the individual pressures of the tyres, or do you have your build code? - look for code 475. Again, if it does, then you have TPMS. Having said that, with some of the comments on the forum about dealers, and trying to order parts from the muppet MB agency in France, I would not be surprised what any dealer said any more!
Our 172 has the build code 475 and individual pressures displayed. I ordered sensors with the winter wheels and tires. I think the sensors were $240 total. I don't think they are an MB part. I got the package from tirerack.com so they were installed, tires mounted and balanced and shipped to my house. When I change wheels, I reset the monitor with steering wheel controls. After a couple of miles the car finds the new sensors and pressures show up. So except for cost, it's no big deal.