B0414

CIRCUIT DESCRIPTION
The air temperature actuator is an electronic device that incorporates a stepper motor and a feedback potentiometer. The HVAC control module determines the position of the air temperature actuator that is based on the voltage from the potentiometer. When the keep alive RAM memory battery power of the HVAC control module is interrupted, the module will calibrate the actuators. The HVAC control module performs a travel range comparison of the determined values of the actuator to the calibrated values within the HVAC control module. If the determined range does not equal the calibrated expected range, the actuator will be considered not calibrated, and the DTC will set. The HVAC control module will also perform a continuous test on the current feedback value. If the feedback value does not fall within the calibrated range, the DTC will set.

CONDITIONS FOR RUNNING THE DTC
^ The ignition is ON.
^ Ignition voltage is between 9-16 volts.
^ The battery power in the keep alive RAM memory of the HVAC control module must be interrupted in order to run the range test.

CONDITIONS FOR SETTING THE DTC
^ The position signal of the air temperature door is out of the range 0.09-4.0 volts (5-250 counts).
^ The total travel range of the air temperature actuator falls without the calibrated limits.

ACTION TAKEN WHEN THE DTC SETS
^ The HVAC control module will continue to make use of whatever travel range is still available.
^ Each time the ignition switch is turned ON, the HVAC control module retests the actuator travel range.

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

DIAGNOSTIC AIDS
^ The range fault can only be detected following a check of the actuator travel range. The actuator travel range test can only be initiated by turning off the power to the HVAC control module.
^ The calibration limit is 64-216 counts. An actual range below this limit suggests an obstruction, something stuck in the door which limits travel. An actual range above this limit suggests an excessive travel condition, damaged, or missing foam seals.
^ A damaged air temperature door or a damaged actuator can cause this DTC to set.
^ An intermittent short to ground on the HVAC class 2 serial data circuit can set this DTC. Recalibrate actuators and test system.
^ If the condition is not present, refer to Testing for Intermittent and Poor Connections in Diagnostic Aids.

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 is within a known calibration range that is stored in the HVAC control module.
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 fuse in the jumper opens when you perform this test, the circuit is shorted to ground.
6. Tests for a short to voltage in the 5-volt reference circuit.