B0446

CIRCUIT DESCRIPTION
The HVAC control module commands right air temperature actuator movement with one of three voltage signals applied to the right air temperature door control circuit. A low voltage of 0 volts moves the right air temperature door toward lull hot. A voltage of 2.5 volts stops the door. A voltage of 5 volts moves the right air temperature door toward full cold. The HVAC control module determines the current position of the actuator by monitoring the feedback voltage of the right air temperature door position signal circuit. The feedback potentiometer position is a function of the actuator position. A high voltage indicates a full hot right air temperature door position. A low voltage indicates a full cold right air temperature door position. The HVAC control module controls the right air temperature door position in order to maintain the selected air temperature. Whenever the HVAC control module keep alive memory battery power is interrupted, the HVAC control module will perform a recalibration of the actuators. During recalibration, the HVAC control module will drive the actuators to their minimum and maximum travel extremes. The HVAC control module will then calculate a travel range from this data and compare it to a calibrated range within the HVAC control module. If the actual travel range is not within the calibrated expected range, the actuator will be considered not calibrated and the DTC will set.

CONDITIONS FOR RUNNING THE DTC
^ The ignition is turned ON.
^ The HVAC control module power must be interrupted.

CONDITIONS FOR SETTING THE DTC
The right air temperature actuator actual total travel range is less than or greater than the calibrated limits.

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

CONDITIONS FOR CLEARING THE DTC
The right air temperature actuator travel range error must be corrected.

DIAGNOSTIC AIDS
^ The range fault code can only be detected following a check of the right air temperature actuator travel range. The right air temperature actuator travel range check can only be initiated by disrupting power to the HVAC control module, disconnecting the battery or with the scan tool.
^ The calibration limit is 147 to 220 counts (2.9 - 4.4 V). An actual range below this limit suggests an obstruction, something stuck in the door limiting travel. An actual range above this limit suggests an over travel condition, damaged or missing foam seals.
^ If condition not present, refer to Testing for Intermittent and Poor Connections in Diagnostic Aids.

TEST

Steps 1-6:

Steps 7-13: