Is the air condition system of my car sealed? Or can coolant be added?
Yes R134 can be added but only if it is determined by a professional . This is not something for do it yourselfers that don’t know what they are doing. You did not provide enough detail to actually let anyone know what your problem is.
Please make up your mind . . .
Do you have a problem with the air conditioning?
Or do you have a problem with the cooling system?
The air conditioning system uses refrigerant . . . most likely R-134a, in your case
The cooling system uses coolant . . .
The air conditioning system of any car had better be sealed (by properly functioning valve cores and service port caps) otherwise the refrigerant will leak out. Yes, refrigerant can be added, but ONLY after a competent technician has determined that the system is indeed low on charge.
If your A/C is already low on charge, I’d recommend having a leak search done before adding refrigerant. This is a 4-year old car, so it hasn’t depreciated into “beater” category yet!
I shudder to think about the consequences resulting from unknowledgeable DIY people who aren’t aware of the incredibly huge difference between refrigerant and coolant.
So why do you ask? A number of things besides low refrigerant (not coolant) can cause an A/C to work improperly. Inoperative cooling fan, faulty blend door, etc. are a few of them.
This vehicle uses R-1234yf refrigerant, the OP may have been told by a shop the they don’t have a machine that can connect to the vehicle leading to the confusion about not being serviceable.
Not all shops have R-1234yf reclaim/recharge stations but Chrysler dealers are required to have them.