B1344

CIRCUIT DESCRIPTION
The Instrument Panel Integration Module (IPM) commands mode actuator movement with 1 of 3 voltage signals applied to the mode door control circuit. A low voltage of 0 volts moves the mode door toward the defrost position. 2.5 volts stops the actuator. 5 volts moves the mode door toward the vent position. The IPM determines the current position of the actuator by monitoring the feedback voltage of the mode door position signal circuit. The feedback potentiometer position is a function of the actuator position. The IPM controls the mode door position in order to maintain the selected air temperature on the HVAC control module.

Whenever the IPM's keep alive memory battery power is interrupted, the IPM will perform a recalibration of the actuators. The IPM will perform a travel range comparison of the calculated minimum and maximum extremes of the actuator to the calibrated minimum and maximum range extremes within the IPM. If the calculated range does not equal the calibrated expected range the actuator will be considered not calibrated and the DTC will set. The IPM will also perform a continuous test on the current feedback value. If the feedback value does not equal or fall within the calibrated range the DTC will set.

CONDITIONS FOR RUNNING THE DTC
^ The ignition is turned ON.
^ The IPMs Keep Alive Memory (KAM) battery power must be interrupted to run the range check. This can be accomplished with the scan tool by commanding HVAC Recalibration in Heating and Air Conditioning Special Functions.

CONDITIONS FOR SETTING THE DTC
The mode actuators total travel range (max-min) is less than or greater than the calibrated limits.

ACTION TAKEN WHEN THE DTC SETS
^ A default value of will be substituted for the mode door position data by the IPM.
^ Each time the ignition switch is turned ON the IPM will recheck the actuator travel range.
^ The IPM will continue to make use of whatever travel range is still available.

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-free ignition cycles.
^ 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 check can only be initiated by disrupting power to the IPM.
^ The calibration limit is 215-245 counts. 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).
^ A damaged or broken air temperature door and or actuator can cause this DTC to set by allowing the actuator shaft to rotate unrestricted to its internal stop. The internal stops are outside of the working range of the feedback potentiometers 0-250 count.

TEST DESCRIPTION

Steps 1-7:

Steps 8-15:

Steps 16-21:

The numbers below refer to the step numbers on the diagnostic table.
8. Tests for the proper operation of the circuit in the high voltage range.
9. 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.
10. Tests for a short to ground in the 5-volt reference circuit.