Diagnostic Instructions
DTC Descriptor
DTC C0379: Front Axle System Malfunction
Circuit/System 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 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 |
| • | An ignition 3 voltage circuit |
When 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 Running the DTC
| • | System voltage is 9-18 volts. |
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 sets if this circuit is high when a low voltage
is present or when the circuit is low when a high voltage is present for 10 seconds. |
| • | The DTC sets if this circuit is high when a low voltage is present or when the circuit is low when a high voltage is present for 10 seconds. |
Action Taken When the DTC Sets
The SERVICE 4WD indicator remains illuminated for the remainder of the current ignition cycle.
Conditions for Clearing the DTC
| • | The transfer case shift control module clears the DTC if the condition for setting the DTC is not currently present. |
| • | A history DTC clears after 100 consecutive ignition cycle without a fault present. |
| • | History DTCs can be cleared using a scan tool. |
Reference Information
Schematic Reference
Transfer Case Control Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Transfer Case Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References
for scan tool information.
Repair Instructions
Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
