Circuit/System Description
WARNING: This page is about a different car, the 2011 GMC Yukon, 2011 Chevrolet Tahoe, and 2011 Cadillac Escalade. However, it is still accessible from the selected car via links, so may be relevant.
The motor temperature sensor is a non-serviceable part of the drive motor generator assembly. The motor temperature sensor is a thermistor, or a resistor that changes value when the temperature changes. The sensor has a negative-temperature coefficient. This means that as the temperature increases, the resistance decreases, and as the temperature decreases, the resistance increases. The motor control module supplies a 5 V reference signal to the sensor and measures the voltage drop in the circuit. When the motor is cold, the sensor resistance is high and the motor control module detects high signal voltage. As the motor temperature increases, the resistance of the sensor decreases, which lowers the signal voltage.