Can you use R134a on the vehicle that call for hfc134a?

Yes, R134a and HFC-134a refer to the same refrigerant, which is 1,1,1,2-tetrafluoroethane. Therefore, if a vehicle specifies HFC-134a, you can use R134a as it is the same chemical compound. However, ensure that the refrigerant meets the manufacturer's specifications and that it is handled properly during servicing.