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U code network Medium severity

U1347 Module Communication Error

The OBD2 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

Definition

The OBD2 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

Common causes

  • 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 misdiagnoses

  • 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  • Software issues or outdated firmware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

Troubleshooting steps

  1. 1. 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

  2. 2. Inspect Wiring and Connectors

  3. 3. Visually inspect the wiring harnesses and connectors associated with the affected modules. Look for signs of damage, corrosion, or loose connections

  4. 4. Pay special attention to ground connections, as poor grounding can lead to communication errors

  5. 5. Check Power Supply

  6. 6. Ensure that the affected modules are receiving the proper voltage. Use a multimeter to check the power supply to the modules

  7. 7. Verify that the fuses related to the communication network are intact

  8. 8. Test the Modules

  9. 9. 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

  10. 10. Inspect the CAN Bus

  11. 11. 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

  12. 12. Use an oscilloscope or a CAN bus analyzer to monitor the communication signals on the bus

  13. 13. Reset the Modules

  14. 14. 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

  15. 15. Update Software/Firmware

  16. 16. 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

  17. 17. Consult Technical Service Bulletins (TSBs)

  18. 18. 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

  19. 19. Professional Diagnosis

  20. 20. 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