NVG 226-NP8 - Transfer Case

DTC C0306

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* 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 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 ranges:

* 2HI
* 4H
* 4LO
* AUTO 4WD
* Neutral


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

* 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 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.
* The transfer case shift control module provides a reference voltage of 4.5 volts on the motor A/B line for diagnostic purposes.



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 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 (NVG 126-NP4 - Transfer Case)
Connector End View Reference

Component Connector End Views
Description and Operation

Transfer Case Description and Operation (NVG 226-NP8 - Transfer Case)
Electrical Information Reference

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

Scan Tool Reference

* Scan Tool Output Controls (Scan Tool Output Controls)
* Scan Tool Data List (Scan Tool Data List)
* Scan Tool Data Definitions (Scan Tool Data Definitions)



Circuit/System Verification

TBD


Circuit/System Testing

TBD


Component Testing

TBD


Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.


Repair Verification

TBD