C0309

DTC C0309

Circuit Description
The transfer case motor is a bi-directional, permanent magnet, D.C. motor. When energized, (through Motor Control A or Motor Control B, the ground is provided by the opposing Motor Control circuit and then grounded through the transfer case shift control module ground circuit), the motor, through a series of gears, rotates a shaft which moves the mode and range forks to shift the transfer case between 4H, AUTO 4WD, 2H, N, and 4L ranges. While the transfer case motor is energized the transfer case shift control module also energizes the solenoid for the transfer case lock. The motor lock is disabled (locking action released) and free turning of the transfer case motor and sector shaft is then allowed.
This DTC detects a short to voltage in the Motor Control A or Motor Control B circuits, or a shorted motor.

Conditions for Setting the DTC
^ The system will test the motor circuits by reading the voltage on each circuit.
^ If the system detects a problem with the circuits, the DTC is logged.
^ The transfer case shift control module senses a high voltage in the Motor Control A or Motor Control B circuits when a low voltage is expected.

Action Taken When the DTC Sets
^ All shifting will be disabled.
^ The 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 no longer exists.
^ A history DTC will clear after 100 consecutive ignition cycles 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. Listen for an audible motor noise when the encoder motor operates. Command both the ON and OFF states. Repeat the commands as necessary.
3. Tests Motor Feed A or the transfer case shift control module for a short to voltage.
4. Tests Motor Feed B or the transfer case shift control module for a short to voltage.
5. Tests Motor Feed A circuit for a short to voltage.
6. Tests Motor Feed B circuit for a short to voltage.