Circuit Description

WARNING: This page is about a different car, the 2003 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.

The following DTCs are for the left and right air temperature actuators:

B0441 is for the left air temperature actuator
B0446 is for the right air temperature actuator

The HVAC control module commands the air temperature actuators to move by controlling the voltage supplied on the control circuit. A signal voltage of 0 volts or a signal voltage of 5 volts rotates the air temperature actuator. A voltage of 2.5 volts stops the door. The HVAC control module determines the current position of the actuator by monitoring the feedback voltage of the air temperature door position signal circuit. The feedback potentiometer position is a function of the air temperature actuator. The HVAC control module controls the air temperature door position in order to maintain the selected air temperature.

Whenever the HVAC control module keep alive memory battery power is interrupted, the HVAC control module will perform a recalibration of the actuators. During recalibration, the HVAC control module will drive the air temperature actuators to their minimum and maximum travel extremes. The HVAC control module will then calculate a travel range from this data and compare it to a calibrated range within the HVAC control module. If the actual travel range is not within the calibrated expected range, the actuator will be considered not calibrated and the DTC will set.