B1344

CIRCUIT DESCRIPTION
The HVAC control module (IPM) commands the mode actuator to move by controlling the voltage on the control circuit. A low voltage of 0 volts moves the door toward the defrost position, 2.5 volts stops the motor, 5 volts moves the door toward the vent position. The IPM determines the current position of the actuator by monitoring the voltage on the feedback circuit. The feedback potentiometer is a function of the motor position. A high voltage of 4-5 volts indicates the vent position. A low voltage of less than 1 volt indicates the defrost position. The IPM controls the mode actuator door positions in order to maintain the selected air outlet.

CONDITIONS FOR RUNNING THE DTC
The ignition is turned ON.

CONDITIONS FOR SETTING THE DTC
The IPM detects the signal circuit is less than 5 counts (0.09 V) or greater than 250 counts (4.90 V).

ACTION TAKEN WHEN THE DTC SETS
A default value will be used for the sensor data by the IPM to move the mode actuator.

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 tree ignition cycles.
^ The DTC can be cleared with a scan tool.

DIAGNOSTIC AIDS
Check the following conditions:
^ A disconnected or broken door may also set this DTC by allowing the mode actuator to travel to its internal stops (overtravel condition).
^ Refer to Testing for Intermittent and Poor Connections in Diagrams.

TEST DESCRIPTION

Steps 1-4:

Steps 5-15:

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.