B0159 SATURN - Ambient Air Temperature Sensor Circuit Range/Performance
Faulty Ambient Air Temperature Sensor
Ambient Air Temperature Sensor harness is open or shorted
Ambient Air Temperature Sensor circuit poor electrical connection
Faulty Heating, Ventilation, and Air Conditioning (HVAC) Control Module
Engine Light ON (or Service Engine Soon Warning Light)
B0159 Saturn Description
The ambient air temperature sensor allows the Heating, Ventilation, and Air Conditioning (HVAC) Control Module to monitor the temperature of the air surrounding the front of the vehicle. The inside air temperature sensor assembly allows the HVAC control module to monitor the temperature of the air inside the passenger compartment. The module applies 5 volts to internal input resistors that are connected to the signal circuits of the air temperature sensors. The module provides ground to the air temperature sensors through the low reference circuits. The HVAC control module monitors the voltage drops across the air temperature sensors and uses the inputs for automatic control calculations. The HVAC control module also uses the ambient air temperature input to calculate the value of the ambient air temperature display. When the air temperatures are cold, the resistances of the sensors are high and the voltage signals are high. When the air temperatures are hot, the resistances of the sensors are low and the voltage signals are low.