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U code network High severity

U2355 U2355: Vehicle Communication Bus Malfunction

The OBD2 code U2355: Vehicle Communication Bus Malfunction indicates a problem with the communication network between various control modules in the vehicle, which may affect their ability to exchange data properly

Definition

The OBD2 code U2355: Vehicle Communication Bus Malfunction indicates a problem with the communication network between various control modules in the vehicle, which may affect their ability to exchange data properly

Common causes

  • Faulty wiring or connectors in the communication bus
  • Malfunctioning control modules
  • Corroded or damaged terminals
  • Short circuits in the wiring harness
  • Interference from aftermarket devices
  • Software issues or bugs in the control modules
  • Poor ground connections
  • Faulty or damaged sensors on the bus
  • Low battery voltage or power supply issues
  • Physical damage to the communication bus system

Common misdiagnoses

  • Faulty ECM (Engine Control Module)
  • Defective BCM (Body Control Module)
  • Wiring issues or shorts in the communication bus
  • Bad ground connections
  • Faulty sensors or actuators
  • Corrupted software or firmware in control modules
  • Battery or power supply issues
  • Incorrectly installed aftermarket accessories or modifications

Troubleshooting steps

  1. 1. Check for Additional Codes

    Use an OBD-II scanner to check for any other trouble codes that may be present. Sometimes, multiple codes can provide more context for the issue

  2. 2. Inspect Wiring and Connectors

    Visually inspect the wiring and connectors associated with the communication bus (CAN bus). Look for signs of damage, corrosion, or loose connections

  3. 3. Pay special attention to the connectors on the Engine Control Module (ECM), Body Control Module (BCM), and any other modules that communicate over the bus

  4. 4. Check for Short Circuits or Open Circuits

    Use a multimeter to check for continuity in the communication lines. Look for any short circuits or open circuits that could disrupt communication

  5. 5. Test the Modules

    If possible, test the individual modules (ECM, BCM, etc.) for proper operation. This may involve using specialized diagnostic tools or software

  6. 6. If a specific module is suspected to be faulty, consider replacing it or reprogramming it if necessary

  7. 7. Inspect the CAN Bus

    Check the CAN bus for proper voltage levels. The typical voltage levels should be around 2.5V to 2.8V when the vehicle is on

  8. 8. Use an oscilloscope to analyze the CAN bus signals for any irregularities or noise

  9. 9. Check for Interference

    Look for any aftermarket devices or modifications that may interfere with the vehicle's communication systems, such as alarms, remote starters, or audio systems

  10. 10. Battery and Ground Connections

    Ensure that the vehicle's battery is in good condition and that all ground connections are secure. Poor grounding can lead to communication issues

  11. 11. Software Updates

    Check if there are any software updates available for the vehicle's modules. Sometimes, manufacturers release updates to fix known communication issues

  12. 12. Clear Codes and Test Drive

    After performing any repairs or adjustments, clear the trouble codes and take the vehicle for a test drive to see if the code reappears

  13. 13. 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 the U2355 code.1

  14. 14. Professional Diagnosis

    If the issue persists after performing the above steps, consider seeking help from a professional mechanic or dealership with experience in diagnosing communication issues. By following these troubleshooting steps, you can systematically identify and resolve the underlying cause of the U2355 code