A process temperature transmitter is operable with at least one temperature sensor having a plurality of leads. The temperature transmitter includes measurement circuitry operably coupleable to the at least one temperature sensor to provide an indication of an electrical parameter of the at least one temperature sensor. A controller is coupled to the measurement circuitry to obtain the indication and provide a process temperature output. A current source applies a test current to the plurality of leads simultaneously. Diagnostic circuitry measures a voltage response on each lead in order to provide a diagnostic indication of the temperature sensor.