U1347 – Module Communication Error

The ODBII code U1347: Module Communication Error indicates a failure in communication between the vehicle’s control modules, often due to a wiring issue, a faulty module, or a problem with the network that connects them.

Moderate.

Common Causes For: U1344: Control Module Communication Fault

• Faulty wiring or connectors
• Failed 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

Common misdiagnosis for U1347: Module Communication Error

• Faulty wiring or connectors
• Defective control module
• Software issues or outdated firmware
• Battery or power supply problems
• Grounding issues
• Intermittent communication faults
• Incorrectly configured aftermarket accessories
• Other communication protocol errors

Common Troubleshooting Steps

The OBD-II code **U1347: Module Communication Error** indicates 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 about the issue.
• Inspect Wiring and Connectors:
• Visually inspect the wiring harnesses and connectors associated with the affected modules. Look for signs of damage, corrosion, or loose connections.
• Pay special attention to ground connections, as poor grounding can lead to communication errors.
• Check Power Supply:
• Ensure that the affected modules are receiving the proper voltage. Use a multimeter to check the power supply to the modules.
• Verify that the fuses related to the communication network are intact.
• Test the Modules:
• If possible, test the affected module(s) to see if they are functioning correctly. This may involve using specialized diagnostic tools or swapping with a known good module.
• Inspect the CAN Bus:
• If your vehicle uses a Controller Area Network (CAN) bus, check for issues with the bus itself. Look for short circuits, open circuits, or other faults in the wiring.
• Use an oscilloscope or a CAN bus analyzer to monitor the communication signals on the bus.
• Reset the Modules:
• Sometimes, simply resetting the modules can resolve communication errors. Disconnect the battery for a few minutes, then reconnect it and see if the code reappears.
• Update Software/Firmware:
• Check if there are any software or firmware updates available for the vehicle’s control modules. Sometimes, communication issues can be resolved with an update.
• Consult Technical Service Bulletins (TSBs):
• Look for any TSBs related to the U1347 code for your specific vehicle make and model. Manufacturers may have identified common issues and provided solutions.
• Professional Diagnosis:
• If the issue persists after performing the above steps, consider seeking help from a professional mechanic or dealership. They may have access to advanced diagnostic tools and resources. By following these troubleshooting steps, you can systematically identify and resolve the underlying cause of the U1347 code.