C0379

DTC C0379

Circuit Description
The front axle control circuit consists of an electric motor actuator which engages and disengages the front axle. The front axle actuator motor consists of a Permanent Magnetic (PM) motor, a worm gear controlled plunger, a front axle switch and an electronic control circuit all within the actuator assembly.

The front axle actuator consists of the following circuits:
^ The front axle control circuit, which is also connected to the transfer case shift control module

The front axle switch circuit, which is also connected to the transfer case shift control module
^ A battery feed circuit
^ A ground circuit

Whenever a shift to AUTO 4WD, 4HI, or 4LO is requested, the transfer case shift control module engages the front axle by grounding the front axle control circuit through a current limiting driver.

This DTC detects a short to ground, short-to-voltage, or an open circuit.

Conditions for Setting the DTC
^ The transfer case shift control module monitors the state of the front axle switch. The transfer case shift control module reads back the front axle switch circuit for a high and low voltage. The DTC will set if this circuit is high when a low voltage is present or when the circuit is low when a high voltage is present.
^ The DTC will set if this circuit is high when a low voltage is present or when the circuit is low when a high voltage is present.

Action Taken When the DTC Sets
^ All shifting for 4WD and AUTO, or the Adapt mode, will be disabled.
^ SERVICE 4WD indicator will be latched on for the remainder of the current ignition cycle.

Conditions for Clearing the DTC
^ The Transfer case shift control module will clear the DTC if the condition for setting the DTC is not currently present.
^ A history DTC will clear after 100 consecutive ignition cycle without a fault present.
^ History DTCs can be cleared using a scan tool.

Test Description
The numbers below refer to the step numbers on the diagnostic table.
2. Tests the front axle circuit for a current malfunction.
3. Helps determine if the failure is the result of a short-to-voltage or ground.
4. Helps determine if the front axle control circuit is shorted to ground.
5. Tests the integrity of the front axle switch and battery feed circuits.
6. Tests the front axle control circuit for short to ground.
7. Tests the front axle switch circuit for short-to-voltage.
8. Tests the front axle battery feed circuit and the front axle switch circuit for an open or short to ground.
9. Tests the front axle control circuit and the front axle ground circuit for an open or high resistance.

DTC C0379 (1 Of 3):

DTC C0379 (2 Of 3):

DTC C0379 (3 Of 3):