I have a new '24 GLC Coupe. I was looking for the tire pressures in the 'service' menu on the driver's screen. They are not there. After multiple attempts to located them, I asked the dealer and they said this particular vehicle (in Mexico) does not have the tire sensors and therefore no monitoring in the service menus. My question is can these be added? Even if I add the sensors to the wheels, will the system recognize them? Or, would this car not have that feature at all?

No, just adding the sensors to the wheels won't work. You also need the receivers in each wheel well along with the coding. The receivers are likely not installed if the vehicle didn't come with TPMS from the factory. Not sure if it's optional in Mexico. Here in the USA, TPMS is mandatory by law. I'm a bit confused. Based on a couple of Google searches it seems TPMS is mandatory in Mexico as well. Specifically for light-duty vehicles model year 2023 and newer the regulation went into effect April 1, 2023. Looks like for passenger vehicles it's been mandatory for even longer.

Yes, I was suprised too. In the manual it doesn't indicate that it would be optional but the dealer is telling me all of this model in Mexico do not have them.

Oh, just to add. There are two types of TPMS systems, direct and indirect. Direct TPMS uses sensors in the wheels and measures the actual pressure and temperature. Indirect TPMS doesn't use sensors in the wheels and instead uses the ABS sensors to measure oscillations in the wheel assembly that are directly tied to tire pressure and using signal processing it can determine if the tire pressure in one or more tires is low. Indirect TPMS is cheaper, but it doesn't have the ability to show actual tire pressures. Your vehicle may be sold with Indirect TPMS in Mexico.

https://en.wikipedia.org/wiki/Tire-p...#Indirect_TPMS

I believe the vehicle does have the ability to indicate a warning if one or more tires has low pressure. On the service screen, it says "Run Flat Indicator is Active' or something like that. That said, the manual says it should have the capability to show individual pressure and temperature. Either way, I'm a little disappointed.

Yep, that looks like you have Indirect TPMS. There would be another menu item under Service | Tires to show the tire pressures in case of Direct TPMS.

Yup "Run Flat indicator" is definitely the indirect one as mentioned, for example here in Canada, the previous gen C-Class sedan W205 C 300 had the indirect and that is the same message shown when checking pressures.