B0252

CIRCUIT DESCRIPTION
The mode actuator is an electronic stepper motor with a feedback potentiometer. The instrument panel integration module (IPM) determines the position of the mode door based on the voltage from the potentiometer. When the airflow is from the vent, the voltage is high. When the airflow is from the defrost outlet, the voltage is low. The IPM controls the mode door position to direct airflow from the outlets selected by the vehicle occupants.

CONDITIONS FOR RUNNING THE DTC
The ignition is turned ON.

CONDITIONS FOR SETTING THE DTC
The IPM detects the mode door position signal is less than 5 counts (0.1 volts) or greater than 250 counts (4.9 volts).

ACTION TAKEN WHEN THE DTC SETS
^ The IPM will only direct airflow from either the vent or defrost outlets.
^ If B0252 sets during a calibration/recalibration event, the IPM will no longer issue commands to the actuator and will not perform a calibration/recalibration until the door position feedback fault is corrected.

CONDITIONS FOR CLEARING THE DTC
^ The DTC will become history if the IPM no longer detects a failure.
^ The history DTC will clear after 50 fault-free ignition cycles.
^ Use the scan tool in order to clear the DTCs.

DIAGNOSTIC AIDS
^ If the condition is not present, refer to Testing for Intermittent and Poor Connections in Diagnostic Aids.
^ A disconnected or broken door/linkage may also set this DTC during calibration/recalibration by allowing the actuator to travel to its minimum internal stop, creating an over travel condition.

TEST DESCRIPTION

Steps 1-3:

Steps 4-12:

Steps 13-16:

The numbers below refer to the step numbers on the diagnostic table.
3. Tests for the proper operation of the circuit in the high voltage range.
4. Tests for the proper operation of the circuit in the low voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to voltage.
5. Tests for a short to ground in the 5 volt reference circuit.