A process fluid temperature transmitter includes a plurality of terminals, an excitation source, a measurement device, and a controller. The plurality of terminals is couplable to an RTD. The excitation source is operably coupled to the plurality of terminals and is configured to apply an excitation signal to the RTD. The measurement device is coupled to the plurality of terminals and is configured to measure a response of the RTD to the applied excitation signal. The controller is coupled to the excitation source and the measurement device. The controller is configured to perform an RTD resistance measurement by causing the excitation source to apply the excitation signal to the RTD and to cause the measurement device to measure the response of the RTD while the excitation signal is applied to the RTD. The controller is also configured to perform an RTD diagnostic by causing the excitation source to change application of the excitation signal and causing the measurement device to measure an RTD response to the changed excitation signal.