C0306

DTC C0306

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.

DTC Descriptor
DTC C0306
- Motor A or B Circuit Malfunction

Circuit/System Description

The transfer case encoder motor is a permanent magnet DC motor and gear reduction assembly. When energized through motor feed A, motor control B provides the ground through the transfer case shift control module ground circuit. The motor, through a series of gears, rotates the sector shaft of the transfer case which applies varying force to a set of clutch plates, controlling the torque applied to the front wheels.

This DTC detects the following conditions:

* An open in the motor feed A or motor control B circuits
* A short to voltage in the motor feed A or motor control B circuits
* A short to ground in the motor feed A or motor control B circuits
* An open in the module ground circuit
* An open inside the motor
* A short to ground inside the motor

Conditions for Running the DTC

* The ignition is ON.
* System voltage is 9-18 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 feed A or motor control B circuits when a high voltage is expected.
* The fault must remain current for 30 seconds to set the DTC.
* The transfer case shift control module provides a reference voltage of 4.5 volts on the motor A/B line for diagnostic purposes.

Action Taken When the DTC Sets

* All shifting is disabled.
* The SERVICE AWD 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.

Reference Information
Schematic Reference

Transfer Case Control Schematics (Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Transfer Case Description and Operation (NVG 126-NP4 - Transfer Case)
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.