The air temperature sensors are a 2-wire negative temperature co-efficient thermistor. The vehicle uses the following air temperature sensors:
* Ambient Air Temperature Sensor
* Inside Air Temperature Sensor Assembly
* Upper Left Air Temperature Sensor
* Upper Right Air Temperature Sensor
* Lower Left Air Temperature Sensor
* Lower Right Air Temperature Sensor
* Upper Auxiliary Air Temperature Sensor
* Lower Auxiliary Air Temperature Sensor
* Auxiliary Inside Air Temperature Sensor
A signal and low reference circuit enables the sensor to operate. As the air temperature surrounding the sensor increases, the sensor resistance
decreases. The sensor signal voltage decreases as the resistance decreases. The sensor operates within a temperature range between -40 to +101锟斤拷C
(-40 to +215锟斤拷F). The sensor signal varies between 0-5 volts. The HVAC control module converts the signal to a range between 0-255 counts. As the
air temperature increases the count value will decrease. If the HVAC control module or auxiliary HVAC control module detects a malfunctioning
sensor, then the control module software will use a defaulted air temperature value. The default value for the ambient and inside air temperature
sensors will be displayed on the scan tool. The default value for the duct air temperature sensors will not be displayed on the scan tool. The scan tool
parameter for the duct air temperature sensors are the actual state of the signal circuit. The default action ensures that the HVAC system can adjust
the inside air temperature near the desired temperature until the condition is corrected.
Diagnostic Aids
Conditions for Running the DTC
Ignition ON.
Conditions for Setting the DTC
The HVAC control module detects the temperature sensor signal circuit is less than -36锟斤拷C (-38锟斤拷F) or greater than 215锟斤拷C (419锟斤拷F) for greater than 15
seconds.
Action Taken When the DTC Sets
The system operates using a default value.
Conditions for Clearing the DTC
* The DTC will become history if the HVAC control module no longer detects the condition that set the DTC.
* The history DTC will clear after 100 fault-free ignition cycles.
Reference Information
Schematic Reference
HVAC Schematics (See: Heating and Air Conditioning/Diagrams/Electrical Diagrams/HVAC - Automatic)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
