U1968 – Module Communication Failure

The ODBII code U1968: Module Communication Failure indicates that there is a communication issue between the vehicle’s control modules, preventing them from exchanging data properly.

The severity of ODBII code **U1968: Module Communication Failure** is generally considered moderate to severe.

Common Causes For: U1963: Module Communication Failure

• Faulty wiring or connectors
• Malfunctioning control module
• Corrupted software or firmware in the module
• Poor ground connections
• Interference from aftermarket devices
• Low battery voltage
• Communication network issues (e.g., CAN bus problems)
• Damaged or corroded pins in connectors
• Incompatible or missing modules in the network

Common misdiagnosis for U1968: Module Communication Failure

• Faulty wiring or connectors
• Defective control module
• Software issues or firmware corruption
• Power supply problems
• Grounding issues
• Intermittent communication issues
• Other communication protocol failures
• Sensor malfunctions

Common Troubleshooting Steps

The OBD-II code **U1968: Module Communication Failure** indicates that there is a communication issue between the vehicle’s control modules. This can be caused by various factors, including wiring issues, faulty modules, or problems with the vehicle’s network. Here are some common troubleshooting steps to diagnose and resolve this issue:

• Check for Other Codes: Use an OBD-II scanner to check for any additional trouble codes. Other codes may provide more context about the issue.
• Inspect Wiring and Connectors:
• Visually inspect the wiring harnesses and connectors associated with the affected module(s) for any signs of damage, corrosion, or loose connections.
• Pay special attention to the ground connections, as poor grounding can lead to communication failures.
• Check Power Supply:
• Ensure that the affected module is receiving the proper voltage and ground. Use a multimeter to check the power supply to the module.
• If the module is not receiving power, trace the wiring back to the fuse box and check for blown fuses or damaged wires.
• Test the Module:
• If possible, test the affected module by swapping it with a known good module (if applicable) to see if the problem persists.
• If the module is not functioning correctly, it may need to be repaired or replaced.
• Inspect the CAN Bus:
• The Controller Area Network (CAN) bus is responsible for communication between modules. Check for any issues with the CAN bus wiring, such as shorts or opens.
• Use an oscilloscope or a CAN bus diagnostic tool to monitor the communication signals on the bus.
• Check for Interference:
• Look for any aftermarket devices or modifications that may interfere with the vehicle’s communication network. This includes alarm systems, stereo systems, or other electronic devices.
• Clear Codes and Test Drive:
• After performing any repairs or adjustments, clear the trouble codes using the OBD-II scanner and take the vehicle for a test drive to see if the code reappears.
• Consult Technical Service Bulletins (TSBs):
• Check for any manufacturer-specific TSBs related to the U1968 code or communication issues for your vehicle make and model. There may be known issues or recommended fixes.
• Professional Diagnosis:
• If the issue persists after performing the above steps, consider seeking help from a professional mechanic or dealership with experience in diagnosing communication issues. By following these troubleshooting steps, you can systematically identify and resolve the underlying cause of the U1968 code.