C0306

DTC C0306

Circuit Description
The transfer case motor is a bidirectional, 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 the following ranges:
^ 4H
^ The AUTO or the Adapt mode
^ 2HI
^ N
^ 4LO

This DTC detects an open, short to voltage, or short to ground in the motor control A or motor control B circuits, or an open, or short to ground inside the motor.

Conditions for Setting the DTC
^ The system will test the motor circuits by checking for unwanted voltage.
^ Then, the system supplies voltage on each of the motor circuits and reads the voltage back on the other circuit.
^ If the system detects a problem with the circuits, the DTC is logged. The transfer case shift control module senses a low voltage return in the motor control A or motor control B circuits when a high voltage is expected.
^ The fault must remain current for 30 seconds to set the DTC.

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.
^ The transfer case shift control module provides a reference voltage of 4.5 volts on the motor A/B line for diagnostic purposes.

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 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. Tests the motor circuit for a current malfunction.
3. Tests the encoder motor for an internal short to ground.
4. Helps isolate motor malfunctions from the transfer case shift control module and wiring.
5. Test for an open, high resistance, short to ground, or short to voltage.

DTC C0306 (1 Of 3):

DTC C0306 (2 Of 3):

DTC C0306 (3 Of 3):