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
^ Neutral

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.

DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC C0306 Motor A or B Circuit Malfunction

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 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 1.2 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 100 consecutive ignition cycles without a fault present.
^ History DTCs can be cleared using a scan tool.

Test Description

Step 1 - Step 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.