U1964 – Module Communication Failure

The ODBII code U1964 indicates a communication failure between modules in the vehicle’s network, suggesting that one or more control modules are not communicating properly with each other.

The severity of ODBII code U1964: Module Communication Failure is generally considered moderate to severe.

Common Causes For: 1. U1771: TCM-ECM Communication Failure

• Faulty wiring or connectors
• Malfunctioning control module
• Poor ground connections
• Interference from aftermarket devices
• Software issues or bugs
• Low battery voltage
• Corroded terminals
• Communication network issues (e.g., CAN bus problems)

Common misdiagnosis for 1. U1964: 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 module failures (e.g., ABS, BCM)

Common Troubleshooting Steps

When dealing with OBD-II code U1964, which indicates a “Module Communication Failure,” it’s important to follow a systematic approach to troubleshoot the issue. Here are common troubleshooting steps:

• Check for Other Codes: Use an OBD-II scanner to check for any additional trouble codes. Sometimes, multiple codes can provide more context about the issue.
• Inspect the Wiring and Connectors:
• Examine the wiring harnesses and connectors associated with the affected module. Look for signs of damage, corrosion, or loose connections.
• Pay special attention to ground connections, as poor grounding can lead to communication issues.
• Verify Power Supply:
• Ensure that the module in question is receiving the proper voltage and ground. Use a multimeter to check the power supply to the module.
• Check the vehicle’s fuses related to the module for any blown fuses.
• Check for Module Functionality:
• If possible, test the affected module by swapping it with a known good module (if applicable) to see if the problem persists.
• Some modules may have self-diagnostic capabilities; check if the module can perform self-tests.
• Inspect the CAN Bus:
• If the vehicle uses a Controller Area Network (CAN) bus, check for communication issues on the bus. Use a scan tool that can monitor CAN bus traffic.
• Look for any short circuits or open circuits in the CAN wiring.
• Update Software/Firmware:
• Check if there are any software or firmware updates available for the vehicle’s modules. Sometimes, communication issues can be resolved with an update.
• Clear Codes and Test Drive:
• After performing the above checks and repairs, 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):
• Look for any TSBs related to the specific make and model of the vehicle. Manufacturers may have issued guidance on common communication issues.
• Professional Diagnosis:
• If the issue persists after performing the above steps, consider seeking help from a professional mechanic or dealership with advanced diagnostic tools. By following these steps, you can systematically identify and resolve the underlying cause of the U1964 code.