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C0329




DTC C0329

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 C0329
- Encoder Signal Circuit Low

Diagnostic Fault Information





Circuit/System Description

The transfer case shift control module (TCCM) has four encoder channels, A, B, C, and P. The TCCM supplies 5 V to each of the four encoder signal circuits. When the TCCM requests motor position it pulls the encoder signal return circuit (low reference) to ground. The status of the four encoder signal circuits is monitored and encoder motor position is determined.

Conditions for Running the DTC

* Ignition ON.
* System voltage is 9-18 V.

Conditions for Setting the DTC

The TCCM can command the low side driver on the encoder signal return circuit not to pull the signal low. The module can then read the voltage on each of the encoder channel circuits. If the voltage is low a short to ground is indicated and the DTC is logged.

Action Taken When the DTC Sets

* The encoder motor shall be stopped, and then commanded towards the 4HI Open position.
* The encoder motor will be deactivated for the remainder of the current ignition cycle.
* All transfer case shift control switch mode indicators will be commanded OFF.
* The SERVICE 4WD indicator will be illuminated for the remainder of the current ignition cycle.
* If a mode change is requested while the DTC is present either current or history, the indicator for the mode requested will flash for 15 seconds and then go out.

Conditions for Clearing the DTC

* The TCCM will clear the DTC once the condition for setting the DTC no longer exists.
* A history DTC will clear after 33 consecutive ignition cycles without a fault present.
* History DTCs can be cleared using a scan tool.

Diagnostic Aids

* EL-49741 - harness is a good source for 9 V.
* EL-49742 - harness is a good source for B+ and ground.
* The transfer case drain plug is a good source for ground.

Reference Information
Schematic Reference

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

Component Connector End Views (Connector End Views By Name)
Description and Operation

Transfer Case Description and Operation (Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

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

Circuit/System Testing

1. Key OFF. Disconnect the X1 connector at the transfer case encoder motor (TCEM).
2. Key ON, engine OFF. Install a scan tool.

Note: When test probing harness terminals, it is imperative to use the proper test probe from the most current version of the J 35616 - Kit. Use of an improper test probe may deform the terminal, resulting in intermittent open conditions.

3. Using the PU probe J 35616-4A, test for 4.3-4.9 V between the encoder motor signal circuits TCEM X1 pins B, C, G and H, and a good ground.

• If the voltage is less than the specified value, test the affected circuit for an open/high resistance or short to ground. If all circuits and connections test normal, test the TCCM for proper operation.
• If the voltage is greater than the specified value, test the affected circuit for a short to voltage. If all circuits and connections test normal, test the TCCM for proper operation.

4. Key OFF.

Note: The TCCM grounds the encoder motor low reference for 10 seconds after key ON.

5. Key ON, engine OFF. Within 10 seconds of key ON, using the PU probes J 35616-4A, test for 4.3-4.9 V between the encoder motor low reference TCEM X1 pin A and the channel A encoder signal circuit TCEM X1 pin H.

• If the voltage is less than the specified value, test the encoder motor low reference circuit for an open/high resistance, short to ground or short together. If all circuits and connections test normal, test the TCCM for proper operation.
• If the voltage is greater than the specified value, test the encoder motor low reference circuit for a short to voltage. If all circuits and connections test normal, test the TCCM for proper operation.

6. While monitoring the encoder channels on the scan tool, using a test light and the PU probe J 35616-4A, individually short to ground each of the encoder channel signal circuits (TCEM X1 pins B, C, G, and H). When an encoder circuit is shorted to ground, does only one encoder channel indicate OFF?

• If more than one of the encoder channels indicates OFF, test the affected circuits for a shorted together condition. If all circuits and connections test normal, test the TCCM for proper operation.
• If an encoder channel signal circuit does not indicate OFF when grounded, test the affected circuit for an open/high resistance or shorted to ground condition. If all circuits and connections test normal, test the TCCM for proper operation.

Note: When removing the transfer case encoder motor, the transfer case will try to move into the Neutral position.

7. Remove the encoder motor from transfer case. Refer to Transfer Case Motor/Encoder Replacement (Service and Repair).
8. Using a paint pen or marker, place indexing marks on the encoder motor drive socket and the mounting surface of the encoder motor.
9. Connect the X1 connector at the transfer case encoder motor (TCEM). Position the TCEM so that the indexing marks are visible from the side of the vehicle.
10. Remove key. Wait 30 seconds. Key ON, engine OFF.
11. With a scan tool, clear codes.
12. Block wheels. Parking brake engaged. Transmission in Neutral.
13. Using the transfer case shift control switch (TCSCS), also known as the accessory or multifunction I/P switch, attempt to shift the transfer case to a different mode.

• If the encoder motor is unable to make the shift, test the TCEM.

14. Inspect the transfer case shift cam and shaft assembly for a binding condition. If binding, remove the transfer case and repair the binding condition.
15. If all circuits and connections test normal, test the TCEM.

Component Testing

TCEM (Transfer Case Encoder Motor) - Motor A and Motor B

Note: When removing the transfer case encoder motor, the transfer case will try to move into the Neutral position.

1. Remove the TCEM from transfer case. Using a paint pen or marker, place indexing marks on the encoder motor drive socket and the mounting surface of the encoder motor.
2. Using a PU probe J-35616-5, attach the red lead from the EL-49741 - jumper harness to the motor control A terminal of the TCEM, pin E.
3. Using a PU probe J-35616-5, attach the black lead from this same jumper harness to the motor control B terminal of the TCEM, pin D.
4. Touch the battery terminals of the 9-volt battery to the battery terminals of the jumper harness. This should rotate the encoder motor drive socket in either a clockwise or counterclockwise rotation depending on battery orientation.

• If the encoder motor drive socket does not rotate, replace the encoder motor.

5. While rotating the TCEM, test for less than 3.0 ohm or greater than 1 M ohm between the encoder low reference circuit, TCEM X1 pin A and each of the encoder signal channel circuits, TCEM X1 pins H, G, C, and B.

• If between 3.0-1 M ohm, replace the TCEM.
• If always less than 3.0 ohm, replace the TCEM.
• If always greater than 1 M ohm, replace the TCEM.

6. Using the EL-49741 - jumper harness, return the TCEM to the marked position of step 1.
7. Test the TCCM.

TCCM
1. Key OFF. Disconnect the X1 connector at the transfer case encoder motor (TCEM).
2. Key ON, engine OFF. Install a scan tool.

Note: When test probing harness terminals, it is imperative to use the proper test probe from the most current version of the J 35616 - Kit. Use of an improper test probe may deform the terminal, resulting in intermittent open conditions.

3. Using the PU probe J 35616-4A, test for 4.3-4.9 V between the encoder motor signal circuits TCEM X1 pins B, C, G, and H and a good ground.

• If the voltage is less than the specified value, test the affected circuit for an open/high resistance or short to ground. If all circuits and connections test normal, replace the TCCM.
• If the voltage is greater than the specified value, test the affected circuit for a short to voltage. If all circuits and connections test normal, replace the TCCM.

4. Key OFF.

Note: The TCCM grounds the encoder motor low reference for 10 seconds after key ON.

5. Key ON, engine OFF. Within 10 seconds of key ON, using the PU probes J 35616-4A, test for 4.3-4.9 V between the encoder motor low reference TCEM X1 pin A and the channel A encoder signal circuit TCEM X1 pin H.

• If the voltage is less than the specified value, test the encoder motor low reference circuit for an open/high resistance, short to ground or short together. If all circuits and connections test normal, replace the TCCM.
• If the voltage is greater than the specified value, test the encoder motor low reference circuit for a short to voltage. If all circuits and connections test normal, replace the TCCM.

6. While monitoring the encoder channels on the scan tool, using a test light and the PU probe J 35616-4A, individually short to ground each of the encoder channel signal circuits (TCEM X1 pins B, C, G, and H). When an encoder circuit is shorted to ground, does only one encoder channel indicate OFF?

• If more than one of the encoder channels indicates OFF, test the affected circuits for a shorted together condition. If all circuits and connections test normal, replace the TCCM.
• If an encoder channel signal circuit does not indicate OFF when grounded, test the affected circuit for an open/high resistance or shorted to ground condition. If all circuits and connections test normal, replace the TCCM.

Repair Instructions

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

* Transfer Case Motor/Encoder Replacement (Service and Repair)
* Transfer Case Disassemble (Transfer Case Disassemble)
* Transfer Case Cleaning and Inspection (Transfer Case Cleaning and Inspection)
* Transfer Case Assemble (Transfer Case Assemble)

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