A vehicle includes a power inverter module (PIM), a motor/generator unit (MGU), vehicle components, temperature sensors, and a controller. The sensors measure temperatures of a motor winding of the MGU, and temperatures of the multiple phase outputs of the PIM. The second plurality of temperature sensors measures temperatures of the vehicle components. The controller calculates an average temperature of the components, and individually diagnoses each temperature sensor using the average temperature. A control circuit for the vehicle includes the first and second plurality of sensors and the controller. A temperature performance diagnostic method includes using the first plurality to measure a temperature of the motor winding and the phase outputs of the PIM, using the second plurality to measure a temperature of the components, calculating an average temperature of the components, and individually diagnosing the performance of each of the first plurality of sensors using the average temperature.