Diagnostic Instructions
DTC Descriptor
DTC C0306 02: Motor A or B Circuit Short to Ground
DTC C0306 05: Motor A or B Circuit Short to Battery or Open
Diagnostic Fault Information
Circuit
| Short to Ground
| Open/High Resistance
| Short to Voltage
| Signal Performance
|
Motor A or B Circuit
| DTC C0306 02
| DTC C0306 05
| DTC C0306 05
| --
|
Circuit/System Description
The transfer case motor is a bi-directional, permanent magnet, DC 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 modes or ranges:
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.
Conditions for Running the DTC
| • | System voltage is 10.5-18 volts. |
Conditions for Setting the DTC
The system tests 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 condition 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 30 seconds to set the DTC. |
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 is not currently present. |
| • | A history DTC clears after 40 consecutive warm up cycles without a fault present. |
| • | History DTCs can be cleared using a scan tool. |
Reference Information
Schematic Reference
Transfer Case Control Schematics
Connector End View Reference
Transfer Case Control Connector End Views
Electrical Information Reference
DTC Type Reference
DTC Symptom Description
Scan Tool Reference
Diagnostic Aids
It is possible to have windings inside the motor shorted to the case resulting in a short to ground causing this DTC to set.
Circuit/System Testing
The motor A control and motor B circuits need to be checked for shorts to ground, opens, high resistance, and shorts to voltage by following the below listed steps.
- With the ignition off disconnect connector X3 from the transfer case control module, and also disconnect the connector at the transfer case actuator.
| ⇒ | With a DMM check the motor A control and motor B control circuits for an open, high resistance, or short to ground and repair as necessary. If all check good go to the next step. |
- Connect X3 at the transfer case control module and turn on the ignition.
- Check to motor A control and motor B control circuits for a short to voltage. If the circuits shows to indication of a short to voltage go to component testing.
Component Testing
- Turn the ignition off and check the motor windings for an internal short to ground inside the motor by probing either the motor A control pin and taking the other lead to ground, or the same can be done using motor B control pin. Motor
control A is pin A and motor B control is pin D.
| ⇒ | If the DMM indicates and short to ground replace the transfer case actuator. If nothing is found continue to the next step. |
- With a DMM check the resistance of the motor windings by probing pin A and pin D on the transfer case actuator.
| ⇒ | The DMM should indicate 0.3-40 ohms, if it does not replace the transfer case actuator and complete the motor learn procedure. If the actuator is within specifications then replace the transfer case control module, program,
and complete the motor learn procedure. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic procedure.
