B0249

CIRCUIT DESCRIPTION
The mode actuator is an electronic device that incorporates a stepper motor and feedback potentiometer. The instrument panel integration module (IPM) 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. The control signal is near 0 V when the mode actuator is commanded toward the defrost position, near 5 V when commanded toward the vent position, and near 2.5 V when stationary. As the mode actuator moves, the potentiometer produces the actual door position signal that is sent to the IPM. The IPM continues to command the actuator to move until the desired and actual values are equal.

When a calibration or recalibration procedure is performed, the IPM calculates the mode door travel range. The IPM commands the actuator through it's full range. The IPM stores the learned minimum and maximum position values. The travel range value is calculated by subtracting the minimum position value from the maximum position value. The IPM compares the travel range to calibrated limits. If the travel range value is less than or equal to the maximum calibrated limit and greater than or equal to the minimum calibrated limit, then the calibration is considered successful. The IPM continuously compares the actual actuator position to the calibrated minimum and maximum position values.

CONDITIONS FOR RUNNING THE DTC
^ The range fault code can only be set following a calibration/recalibration of the mode actuator.
^ The IPM will not perform a calibration/recalibration of the mode actuator if DTC B0252 is set as current.

CONDITIONS FOR SETTING THE DTC
The actual total travel range of the mode door, max - minis less than 200 counts or greater than 246 counts.

ACTION TAKEN WHEN THE DTC SETS
^ The IPM will continue to make use of whatever travel range is still available.
^ The IPM will recalibrate the mode door travel range each time the ignition switch is turned ON.

CONDITIONS FOR CLEARING THE DTC
^ A successful recalibration of the mode door must be completed.
^ A 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.
^ The calibration limit is 200-246 counts (3.9-4.8 V). An actual range below this limit suggests an obstruction of the mode door or a binding linkage limiting travel. An actual range above this limit suggests an over travel condition, damaged or missing foam seals.

TEST DESCRIPTION

Steps 1-8:

Steps 9-16:

The numbers below refer to the step numbers on the diagnostic table.
3. A total travel range greater than 15 counts indicates a mechanical malfunction with the door or linkage, causing an over travel or under travel condition. A total travel range less than 15 counts indicates an electrical malfunction, binding door, or binding linkage.
8. This step uses the fused jumper wire to drive the actuator to its maximum and minimum positions. Use the scan tool to determine the total travel range of the actuator, maximum position - minimum position.