A diagnostic system for a thermistor amplifier circuit of a motor control system, comprising: a transistor being electrically coupled in series with a resistor, the transistor having an input terminal, a first output terminal, and a second output terminal, the first output terminal being electrically coupled to the thermistor amplifier circuit, the resistor being electrically coupled between the second output terminal and electrical ground; the transistor configured to apply a first test voltage signal to the thermistor amplifier circuit in response to receiving a second control signal from a microprocessor, an amplitude of the first test voltage signal being indicative of a first simulated thermistor temperature value; the microprocessor configured to determine an amplitude of a first output voltage of the thermistor amplifier circuit and to determine a first test temperature value based on the amplitude of the first output voltage; and the microprocessor further configured to determine a first inaccuracy value based on the first test temperature value and the first simulated thermistor temperature value, characterized in that: the resistor is a controllable variable resistor configured to have a first predetermined resistance in response to receiving a first control signal from the microprocessor, to have a second predetermined resistance in response to receiving a fourth control signal from the microprocessor, and to have a third predetermined resistance in response to receiving a sixth control signal from the microprocessor; and the diagnostic system comprises an input device configured to allow a user to input an acceptable inaccuracy range and a display device operably coupled to the microprocessor, the display device configured to display the first inaccuracy value and to display a warning message when the first inaccuracy value is outside of the acceptable inaccuracy range. a transistor being electrically coupled in series with a resistor, the transistor having an input terminal, a first output terminal, and a second output terminal, the first output terminal being electrically coupled to the thermistor amplifier circuit, the resistor being electrically coupled between the second output terminal and electrical ground; the transistor configured to apply a first test voltage signal to the thermistor amplifier circuit in response to receiving a second control signal from a microprocessor, an amplitude of the first test voltage signal being indicative of a first simulated thermistor temperature value; the microprocessor configured to determine an amplitude of a first output voltage of the thermistor amplifier circuit and to determine a first test temperature value based on the amplitude of the first output voltage; and the microprocessor further configured to determine a first inaccuracy value based on the first test temperature value and the first simulated thermistor temperature value, characterized in that: the resistor is a controllable variable resistor configured to have a first predetermined resistance in response to receiving a first control signal from the microprocessor, to have a second predetermined resistance in response to receiving a fourth control signal from the microprocessor, and to have a third predetermined resistance in response to receiving a sixth control signal from the microprocessor; and the diagnostic system comprises an input device configured to allow a user to input an acceptable inaccuracy range and a display device operably coupled to the microprocessor, the display device configured to display the first inaccuracy value and to display a warning message when the first inaccuracy value is outside of the acceptable inaccuracy range. the resistor is a controllable variable resistor configured to have a first predetermined resistance in response to receiving a first control signal from the microprocessor, to have a second predetermined resistance in response to receiving a fourth control signal from the microprocessor, and to have a third predetermined resistance in response to receiving a sixth control signal from the microprocessor; and the diagnostic system comprises an input device configured to allow a user to input an acceptable inaccuracy range and a display device operably coupled to the microprocessor, the display device configured to display the first inaccuracy value and to display a warning message when the first inaccuracy value is outside of the acceptable inaccuracy range.