C0359
DTC C0359
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 C0359
- Four Wheel Drive Low Range (4WD low) Discrete Output Circuit Malfunction
Circuit/System Description
The 4WD LO circuit is used to notify the powertrain control module (PCM) that the vehicle is in 4WD LO range. The PCM supplies 12 volts to this circuit. The transfer case shift control module (TCCM) grounds this circuit when the vehicle is in 4WD LO range.
This DTC detects a short-to-ground, short-to-voltage, or an open in the 4WD LO circuit.
Conditions for Running the DTC
* Ignition ON.
* System voltage 9-18 V.
Conditions for Setting the DTC
* The TCCM reads a low voltage, when a high voltage is expected, on the 4WD LO circuit.
* The TCCM thermal model inside the 4WD LO driver signals an over temperature condition.
Action Taken When the DTC Sets
* The transmission shift points may be affected.
* The SERVICE 4WD indicator remains illuminated for the remainder of the current ignition cycle.
Conditions for Clearing the DTC
* The TCCM clears the DTC once the conditions for setting the DTC no longer exist.
* 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-49742 - harness is a good source for B+ and ground.
* A diagnostic voltage does not supply enough current to light a test light.
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.
Special Tools
* EL-49742 - Battery Voltage B+ and Ground Source Harness
* J 35616 - GM-Approved Terminal Test Kit
Circuit/System Verification
Note: It may be necessary to drive the vehicle slightly forward to engage 4LO on the transfer case.
1. Key ON, engine OFF.
2. Parking brake ON, transmission in Neutral.
3. Using the Transfer Case Data display functionality of the scan tool, verify that the Mode Switch Selected, Encoder Gear Position/Transfer Case Position and corresponding Indicator Light parameters all match when using the transfer case shift control switch (TCSCS) to change modes.
• If the scan tool indicates different than stated, refer to Symptoms - Transfer Case (Symptoms - Transfer Case)
4. Using the scan tool, verify that the 4WD Low Active parameter reads Yes/No when using the TCSCS to go In/Out of 4WD Low.
• If the parameter does not perform as specified, suspect a 4WD LO signal circuit or control module condition.
Circuit/System Testing
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.
1. Key OFF. Disconnect the X1 connector at the TCCM.
2. Key ON, engine OFF. Install a scan tool.
3. Using the BN probe J 35616-6, test for a diagnostic B+ (+0.0/-1.0 V) between the 4WD LO signal circuit, TCCM X1 harness pin B5, 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 PCM/ECM for proper operation.
4. Using the BN probe J 35616-6, connect a test light between the 4WD LO signal circuit, TCCM X1 harness pin B5, and a good ground. The test light should not illuminate.
• If the test light illuminates, test the affected circuit for a short to voltage. If all circuits and connections test normal, test the PCM/ECM for proper operation.
Component Testing
PCM/ECM/TCM
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.
1. Key OFF. Disconnect the X1 connector at the TCCM.
2. Key ON, engine OFF. Install a scan tool.
3. Monitor the 4WD LO parameter on the scan tool. The 4WD LO parameter should read disabled.
• If the 4WD LO parameter reads enabled, test the 4WD LO circuit for a short to ground. If all circuits and connections test normal, replace the PCM/ECM.
4. Using a BN probe J 35616-6, connect a fused jumper between the 4WD LO signal circuit, TCCM X1 harness pin B5, and a good ground. When grounded the 4WD LO parameter should read enabled.
• If the 4WD LO parameter reads disabled, test the 4WD LO circuit for an open/high resistance condition. If all circuits and connections test normal, replace the PCM/ECM.
5. Using the BN probe J 35616-6, test for greater the 1 K ohm between the 4WD LO signal circuit, TCCM X1 harness pin B5, and all other pins of the TCCM X1 connector.
• If the resistance is less than the stated value, test the affected circuits for a short together condition. If all circuits and connections test normal, replace the PCM/ECM.
6. If all circuits, connections, and the PCM/ECM test normal, replace the TCCM.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.