Diagnostic Instructions
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 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.
Reference Information
Schematic Reference
Transfer Case Control Schematics
Connector End View Reference
Component Connector End Views
Electrical Information Reference
Scan Tool Reference
Control Module References
for scan tool information.
Circuit/System Testing
- If this is occurring without DTC C0379 setting it is likely related to a mechanical issue. Refer to
Four-Wheel Drive Does Not Engage
.
- If no mechanical issue is found replace the front axle actuator.
Repair Instructions
Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
