C0308

Circuit Description
The transfer case motor is a bi-directional, permanent magnet, DC motor. When energized, (through CKTS 1552, 1553, and the ground CKT 150 the module utilize for the motor control), 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 (Adapt), 2H, N, and 4L ranges.
This DTC detects a short to ground on CKT 1552 and 1553.
Conditions for Setting the DTC
^ The system will test the motor circuits:
^ The system checks for unwanted voltage.
^ The system supplies voltage on one circuit and reads the voltage back on the other.
^ If the system detects a problem with the circuits, the DTC is logged.
^ The transfer case shift control module senses a low voltage return on CKT 1552 or 1553 when a high voltage is expected.
Action Taken When the DTC Sets
^ All shifting will be disabled.
^ The SERVICE indicator (AWD/4WD) lamp will be latched on for the remainder of the current ignition cycle.
Conditions for Clearing the MIL/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 number(s) below refer to the step number(s) on the diagnostic table.
2. Listens for an audible motor noise when the encoder operates. Command both the ON and OFF states. Repeat the commands as necessary.
3. Tests for a short to ground in the Motor Control A circuit or module.
4. Tests for a short to ground in the Motor Control B circuit or module.
5. Tests for a higher than normal resistance in the Motor Control A and B circuits and through the module.
6. Tests for a short to ground in the encoder motor windings.
7. Tests for continuity across the motor circuit. Resistance readings vary depending on the location of brush contact inside the motor assembly.
8. Tests Motor Control A circuit for a short to ground.
9. Tests Motor Control B circuit for a short to ground.
10. Tests Motor Control A and B circuits for an open or high resistance.