C0308

DTC C0308

Test 1-3:

Test 4-13:

Circuit Description
The transfer case motor is a bidirectional, permanent magnet, DC motor. When energized through motor control A or motor control B, the ground is provided by the opposing motor control circuit, 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.

This DTC detects a short to ground in motor control A or motor control B circuit.

Conditions for Running the DTC
^ The ignition is ON.
^ System voltage is 9 - 16 volts.

Conditions for Setting the DTC
^ The system tests the motor circuits.
^ First, the system checks for unwanted voltage.
^ Then, the system supplies voltage on one circuit and reads the voltage back on the other.
^ If the system detects a condition with the circuits, the DTC is logged.
^ The transfer case shift control module senses a low voltage return in motor control A or motor control B when a high voltage is expected.

Action Taken When the DTC Sets
^ All shifting is disabled.
^ The SERVICE 4WD indicator remains illuminated for the remainder of the current ignition cycle.

Conditions for Clearing the DTC
^ The transfer case shift control module clears the DTC if the condition for setting the DTC no longer exists.
^ A history DTC clears after 100 consecutive ignition cycles without a fault present.
^ History DTCs can be cleared using a scan tool.

Test Description
The numbers refer to the step numbers on the diagnostic table.
2. This step listens for an audible motor noise when the encoder motor operates. Command both the ON and OFF states. Repeat the commands as necessary.
3. This step tests for a short to ground in the motor control A circuit.
4. This step tests for a short to ground in the motor control B circuit.
5. This step tests for a higher than normal resistance in the motor control A and B circuits through the module.
6. This step tests for a short to ground in the encoder motor windings.
7. This step tests for continuity across the motor circuit. Resistance readings vary depending on the location of the brush contact inside the motor assembly.
8. This step tests motor control A circuit for a short to ground.
9. This step tests motor control B circuit for a short to ground.
10. This step tests motor control A and B circuits for an open or high resistance.