Brief description of components

The transmission temperature sensor is a thermistor where the output value changes according to the transmission oil temperature. The sensor has negative temperature coefficient. With rising temperature, the resistance falls and with falling temperature the resistance increases. The EGS control module sends a reference signal to the sensor and measures the voltage drop in the circuit. At low transmission oil temperature, the sensor resistance is high and the EGS control module picks up a high signal voltage. When the transmission oil temperature rises, the resistance becomes lower and the signal voltage drops.

Fig 1: Identifying Electronic Module Components

Courtesy of BMW OF NORTH AMERICA, INC.