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.

DTC Descriptor
This diagnostic procedure supports this DTC:
DTC C0309 Motor A/B Circuit High

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.

History DTC
^ A history DTC clears after 100 consecutive ignition cycles without a fault present.
^ History DTCs can be cleared using a scan tool.

Test Description





These numbers correspond 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.