U1963 – Module Communication Failure

The ODBII code U1963: 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 **U1963: Module Communication Failure** is generally considered moderate to severe, depending on the specific vehicle and the affected systems.

Common Causes For: U1948: 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
• Faulty or damaged sensors affecting communication

Common misdiagnosis for U1963: Module Communication Failure

• Faulty wiring or connectors
• Defective control module
• Software issues or updates needed
• Battery or power supply problems
• Grounding issues
• Intermittent communication issues
• Other communication protocol failures
• Sensor malfunctions

Common Troubleshooting Steps

The OBD-II code **U1963: 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 Additional Codes: Use an OBD-II scanner to check for any other trouble codes that may be present. This can provide more context and help identify the root cause of the communication failure.
• Inspect Wiring and Connectors:
• Visually inspect the wiring and connectors associated with the affected modules. Look for signs of damage, corrosion, or loose connections.
• Pay special attention to the wiring harnesses that connect the modules, as these can be prone to wear and tear.
• Check Power and Ground:
• Ensure that the affected module(s) are receiving proper power and ground. Use a multimeter to check voltage and ground continuity.
• If the module is not receiving power, trace the wiring back to the fuse box and check for blown fuses or damaged wiring.
• Test the Affected Module:
• If the wiring and power supply are good, the module itself may be faulty. If possible, test the module by swapping it with a known good module or using a diagnostic tool to perform a module self-test.
• If the module is not responding, it may need to be repaired or replaced.
• Check for Network Issues:
• Inspect the CAN (Controller Area Network) bus for issues. Use a scan tool to monitor the communication between modules and check for any abnormalities.
• Look for any signs of interference or issues with the termination resistors on the CAN bus.
• Clear Codes and Test Drive:
• After addressing any identified issues, clear the trouble codes using the OBD-II scanner and take the vehicle for a test drive to see if the code returns.
• Monitor the vehicle’s performance and check for any warning lights.
• Consult Technical Service Bulletins (TSBs):
• Check for any manufacturer-specific TSBs related to U1963 or module communication issues. There may be known fixes or updates available.
• Professional Diagnosis:
• If the issue persists after performing the above steps, consider seeking help from a professional mechanic or dealership. They may have specialized diagnostic tools and experience with your specific vehicle make and model. By following these steps, you can systematically diagnose and potentially resolve the U1963 code and its underlying communication issues.