B0248

CIRCUIT DESCRIPTION
The mode actuator is an electronic device that incorporates a stepper motor and feedback potentiometer. The HVAC control module controls the mode door position by sending a control signal to the actuator. The signal's value is dependent upon the desired mode selected by the vehicle occupants. As the actuator moves, the potentiometer produces the actual door position signal that is sent to the HVAC control module. The HVAC control module continues to command the actuator to move until the desired and actual values are equal. The door directs airflow through the outlets as selected by the vehicles occupants.

CONDITIONS FOR RUNNING THE DTC
^ The ignition is ON.
^ Ignition voltage is between 9-16 volts.
^ An mode actuator positional change is attempted.

CONDITIONS FOR SETTING THE DTC
The actual mode door position differs from the commanded mode door position by 4 counts or more.

ACTION TAKEN WHEN THE DTC SETS
The mode actuator is considered stalled and the HVAC control module will command the mode actuator to stop rotation (2.5 V).

CONDITIONS FOR CLEARING THE DTC
^ If the HVAC control no longer detects a failure, then the DTC will become history.
^ The history DTC will clear after 50 ignition cycles without a failure.
^ The DTC can be cleared with a scan tool.

DIAGNOSTIC AIDS
^ A dead zone exists in a range 10 counts above or below the mode door max or mode door mm positions. When the mode door actual data parameter is within the dead zone, the DTC will not set. If the mode door commanded data parameter differs from the mode door actual data parameter by 4 counts or more outside the dead zone, the DTC will set.
^ A damaged or broken mode door and or actuator can cause this DTC to set.

TEST

Steps 1-5:

Steps 6-13: