C0309

DTC C0309

Circuit Description
The transfer case encoder motor is a permanent magnet DC motor and gear reduction assembly. The encoder motor is controlled with a Pulse Width Modulated (PWM) circuit within the transfer case shift control module. This circuit consists of Motor Control A, a power supply relay circuit that supplies voltage to the motor. The Motor Control B circuit is a PWM driver that varies the duty cycle to control the amount of current through the motor to ground.

This DTC detects a short to power on the Motor Control A circuit or the Motor Control B circuit.

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

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

Action Taken When the DTC Sets
^ The SERVICE AWD indicator remains illuminated for the remainder of the current ignition cycle.
^ All clutch activation, slip control is disabled.

Conditions for Clearing the DTC
^ Current 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 below refer to the step numbers on the diagnostic table.
2. This step tests Motor Control A for an open or short to voltage.
3. This step tests Motor Control B for an open or short to voltage.
4. This step tests for continuity across the motor windings.

Steps 1 - 7:

DTC C0309