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U code network High severity

U1311 Module Communication Failure

The OBD2 code U1311 indicates a communication failure between modules in the vehicle's network, suggesting that one or more control modules are not able to communicate properly with each other

Definition

The OBD2 code U1311 indicates a communication failure between modules in the vehicle's network, suggesting that one or more control modules are not able to communicate properly with each other

Common causes

  • Faulty wiring or connectors
  • Failed control module
  • Poor ground connections
  • Intermittent communication issues
  • Corrupted software or firmware
  • Low battery voltage
  • Electrical interference
  • Damaged or corroded pins in connectors

Common misdiagnoses

  • 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)
  • Incorrectly configured aftermarket accessories

Troubleshooting steps

  1. 1. Check for Additional Codes

    Use an OBD-II scanner to check for any other trouble codes that may be present. Other codes can provide context and help identify the root cause of the communication failure

  2. 2. Inspect Wiring and Connectors

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

  3. 3. Pay special attention to the ground connections, as poor grounding can lead to communication issues

  4. 4. Check Module Power Supply

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

  5. 5. If a module is not receiving power, trace the wiring back to the fuse box and check for blown fuses or damaged wires

  6. 6. Test Communication Lines

    Use a scan tool to check the communication lines (CAN bus, LIN bus, etc.) for proper operation. You can use a multimeter or an oscilloscope to check for signal integrity

  7. 7. Look for short circuits, open circuits, or noise on the communication lines

  8. 8. Check for Module Malfunction

    If the wiring and connections are good, the issue may be with the module itself. If possible, swap the suspected module with a known good one to see if the problem persists

  9. 9. If the module is faulty, it may need to be repaired or replaced

  10. 10. 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 properly

  11. 11. Reset the Codes

    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 returns

  12. 12. Consult Technical Service Bulletins (TSBs)

    Check for any TSBs related to the specific make and model of the vehicle. Manufacturers may have issued guidance on common communication issues

  13. 13. Seek Professional Help

    If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or technician who has experience with the specific vehicle and its systems. By following these troubleshooting steps, you can systematically identify and resolve the underlying issue causing the U1311 code