B0229

CIRCUIT DESCRIPTION
The recirculation actuator is an electronic device that incorporates a stepper motor and feedback potentiometer. The HVAC control module controls the recirculation 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 recirculation 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.

After a calibration or recalibration procedure is performed, the HVAC control module calculates the recirculation actuator travel range. The HVAC control module commands the actuator through it's full range. The HVAC control module stores the learned minimum and maximum position values. The travel range value is calculated by subtracting the minimum and maximum position values. The HVAC control module compares the travel range, minimum and maximum values to calibrated value ranges. 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 HVAC control module continuously compares the actual actuator position to the calibrated minimum and maximum position values.

CONDITIONS FOR RUNNING THE DTC
^ The ignition is ON.
^ Ignition voltage is between 9-16 volts.
^ The HVAC control module keep alive memory battery power must be interrupted to run the range check (recalibration procedure).

CONDITIONS FOR SETTING THE DTC
^ Recirculation actuator position signal is less than 5 counts.
^ Recirculation actuator position signal is more than 250 counts.
^ The recirculation actuators total travel range (min-max) is less than or greater than the calibrated limits.

ACTION TAKEN WHEN THE DTC SETS
^ The DTC is stored in DTC information.
^ The HVAC control module will continue to make use of whatever travel range is still available.

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 short to voltage on the 5-volt reference circuit of the recirculation actuator will cause DTC B0229 and DTC B0414 to set.
^ A damaged or broken recirculation door and or actuator can cause this DTC to set.
^ The range fault can only be detected following a check of the actuator travel range. The actuator travel range check (recalibration procedure) can only be initiated by disrupting power to the HVAC control module.

TEST DESCRIPTION

Steps 1-7:

Steps 8-13:

The numbers below refer to the step numbers on the diagnostic table.
2. This step determines if the air temperature door position is within the specified range of the commanded value.
4. Tests for the proper operation of the circuit in the low voltage range.
5. Tests for the proper operation of the circuit in the high voltage range. If the jumper fuse opens when you perform this test, then the signal circuit contains a short to ground.
6. Tests for a short to voltage in the 5-volt reference circuit.