C0306

DTC C0306

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 the following ranges:
- 4HI
- 4HI Lock
- 4LO Lock
- N

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 RUNNING THE DTC
- The ignition is ON.
- The system voltage is 9-18 volts.

CONDITIONS FOR SETTING THE DTC
- The system will test the motor circuits by testing 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 remain illuminated 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 33 consecutive ignition cycles without a fault present.
- History DTCs can be cleared using a scan tool.

TEST DESCRIPTION

Steps 1-2:

Steps 3-11:

The numbers below refer to the step numbers on the diagnostic table.
2. This step tests motor A driver high for proper operation.
3. This step tests motor B driver high for proper operation.
4. This step tests motor A driver low for proper operation.
5. This step tests motor B driver low for proper operation.
6. This step tests motor control A and motor control B circuits for being shorted-together.
7. This step tests motor control A for a short to ground, short to voltage, open, or high resistance.
8. This step tests motor control B for a short to ground, short to voltage, open, or high resistance.