Circuit/System Description

The automatic transmission fluid temperature sensor provides transmission fluid temperature to the transmission control module (TCM). The TCM supplies a 5 V reference signal to the sensor. The automatic transmission fluid temperature sensor is a variable resistor that measures the temperature of the transmission fluid, the value changes when the temperature changes. The sensor has a negative temperature coefficient. This means that as the temperature increases the resistance decreases and vice versa. The TCM will compare the temperature difference between the engine coolant temperature sensor and the automatic transmission fluid temperature sensor to determine if the temperatures are within an acceptable operating range of each other. This fault is handled inside the TCM and no external circuits are involved.