WOMS
U code network High severity

U1346 U1346: Control Module Communication Failure

The OBD2 code U1346 indicates a communication failure between control modules in a vehicle, suggesting that one or more modules are not properly communicating with each other

Definition

The OBD2 code U1346 indicates a communication failure between control modules in a vehicle, suggesting that one or more modules are not properly communicating with each other

Common causes

  • Faulty control module
  • Poor electrical connections
  • Damaged wiring harness
  • Corroded connectors
  • Software issues or bugs
  • Low battery voltage
  • Interference from aftermarket devices
  • Faulty sensors or actuators
  • Grounding issues
  • Communication network failure (e.g., CAN bus issues)

Common misdiagnoses

  • Faulty control module
  • Wiring issues or shorts
  • Poor ground connections
  • Corrupted software or firmware
  • Faulty sensors
  • Battery or power supply problems
  • Communication network issues (CAN bus problems)
  • Intermittent connection issues

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 additional context for the issue

  2. 2. Inspect Wiring and Connectors

    Visually inspect the wiring and connectors associated with the control 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 for Short Circuits

    Use a multimeter to check for short circuits in the wiring harnesses. Ensure that there are no unintended connections between wires

  5. 5. Test Control Modules

    If possible, test the affected control modules to ensure they are functioning correctly. This may involve using specialized diagnostic tools or swapping with known good modules

  6. 6. Inspect the CAN Bus

    The Controller Area Network (CAN) bus is responsible for communication between control modules. Check for any issues with the CAN bus wiring, such as breaks or shorts

  7. 7. Use an oscilloscope to monitor the CAN bus signals if you have access to one

  8. 8. Check for Software Updates

    Sometimes, communication issues can be resolved with a software update. Check with the vehicle manufacturer for any available updates for the control modules

  9. 9. Clear Codes and Test Drive

    After performing any repairs or inspections, clear the trouble codes using the OBD-II scanner and take the vehicle for a test drive to see if the code returns

  10. 10. 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 issues related to U1346

  11. 11. 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

  12. 12. Check Battery and Charging System

    Ensure that the vehicle's battery and charging system are functioning properly. Low voltage can cause communication issues between control modules. By following these steps, you should be able to identify and resolve the underlying cause of the U1346 code. Always refer to the vehicle's service manual for specific diagnostic procedures and specifications