U1731 – Module Communication Failure

The ODBII code U1731 indicates a “Module Communication Failure,” meaning there is a problem with communication between the vehicle’s control modules, often due to a wiring issue, a faulty module, or a network problem.

The severity of ODBII code U1731 is moderate.

Common Causes For: U1730 U1730: “Module Communication Failure”

• Faulty wiring or connectors
• Failed or malfunctioning control module
• Poor ground connections
• Corroded or damaged pins in connectors
• Communication network issues (e.g., CAN bus problems)
• Software or firmware issues in modules
• Intermittent electrical connections
• Low battery voltage or power supply issues

Common misdiagnosis for U1731 U1731: “Module Communication Failure”

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

Common Troubleshooting Steps

The OBD-II code U1731 indicates a “Module Communication Failure,” which typically means that there is a problem with communication between the vehicle’s control modules. Here are some common troubleshooting steps to diagnose and resolve this issue:

• Check for Other Codes: Start by scanning the vehicle for any other diagnostic trouble codes (DTCs). Other codes may provide additional context or indicate related issues.
• Inspect Wiring and Connectors:
• Check the wiring harnesses and connectors associated with the affected module(s) for any 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 affected module is receiving the proper voltage and ground. Use a multimeter to check the power and ground circuits.
• If the module is not powered correctly, trace the wiring back to the power source.
• Check for Module Faults:
• If the module itself is faulty, it may not communicate properly. If possible, test the module in another vehicle or replace it with a known good module to see if the issue persists.
• Inspect the CAN Bus:
• If the vehicle uses a Controller Area Network (CAN) bus for communication, check the integrity of the CAN bus wiring. Look for shorts, opens, or interference.
• Use an oscilloscope to check the CAN bus signals if you have access to one.
• Perform a Network Test:
• Some advanced scan tools can perform a network test to check the communication between modules. This can help identify which module is not communicating.
• Check for Software Updates:
• Sometimes, communication issues can be resolved with a software update. Check with the manufacturer for any available updates for the affected module(s).
• Clear Codes and Test Drive:
• After performing the above checks and repairs, clear the codes and take the vehicle for a test drive to see if the U1731 code returns.
• 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.
• Seek Professional Help:
• If the issue persists after performing these steps, it may be necessary to consult a professional technician or a dealership with specialized diagnostic equipment. By following these steps, you should be able to identify and resolve the underlying cause of the U1731 code.