Circuit/System Description

The B9 Ambient Air Temperature Sensor is located behind the grille. The engine control module monitors the ambient air temperature sensor with a low reference circuit and signal circuit. The engine control module monitors the voltage drop across the sensor, which is inversely proportional to temperature. When the ambient air temperature is cold, the resistance of the sensor is high. When the ambient air temperature is warm, the resistance of the sensors is low. The engine control module converts the voltage value to a temperature value and sends the value to the P17 Info Display Module via serial data. The P17 Info Display Module displays the temperature.