2010 Cadillac CTS Sedan AWD V6-3.6L Page 204
Circuit/System Description
The HVAC control module controls the HVAC door actuators to regulate the airflow through the HVAC system. Each actuator consists of an
electric motor and a potentiometer. The module supplies a low reference and 5-volt reference source voltage to the potentiometer. The HVAC
control module monitors the voltage drop across the potentiometer on the door position signal circuit. When the actuator shaft rotates, the voltage
on the door position signal circuit changes. The HVAC module controls the direction of the actuator door by changing the polarity of the control
circuits.
* Air Flow Control 3 is the mode actuator
* Air Flow Control 7 is the recirculation actuator
* Temperature Control 1 is the left temperature actuator
* Temperature Control 2 is the right temperature actuator
Conditions for Running the DTC
* Ignition ON.
* Ignition voltage is between 9-16 volts.
* The HVAC module is ON.
Conditions for Setting the DTC
The actual door position differs from the commanded door position by more than 4 counts or the HVAC control module detects the door position
signal circuit is less than 7 counts or greater than 250 counts.
Action Taken When the DTC Sets
Control A and control B circuits are deactivated for the appropriate actuator.
Conditions for Clearing the DTC
* The DTC becomes history when the HVAC control module no longer detects the condition that set the DTC.
* The history DTC will clear after 50 fault-free ignition cycles.
