Circuit/System Description
WARNING: This page is about a different car, the 2008 GMC Yukon and 2008 Chevrolet Tahoe. However, it is still accessible from the selected car via links, so may be relevant.
The motor temperature sensor (MTS) is a non-serviceable part of the drive motor generator assembly. The MTS 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 (MCM) supplies about a 5-volt 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 MCM detects high signal voltage. As the motor temperature increases, the resistance of the sensor decreases, which lowers the signal voltage.