WOMS
U code network Medium severity

U2535 U2535: Vehicle Communication Bus Malfunction

The OBD2 code U2535: Vehicle Communication Bus Malfunction indicates a problem with the communication between various control modules in the vehicle, which may affect their ability to exchange data properly

Definition

The OBD2 code U2535: Vehicle Communication Bus Malfunction indicates a problem with the communication 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 connectors
  • Short circuits in the communication lines
  • Open circuits in the communication lines
  • Software issues or bugs in the control modules
  • Interference from aftermarket devices
  • Low battery voltage or poor ground connections

Common misdiagnoses

  • Faulty OBDII connector
  • Bad ground connections
  • Defective ECM (Engine Control Module)
  • Malfunctioning BCM (Body Control Module)
  • Wiring issues or shorts in the communication lines
  • Faulty sensors or actuators
  • Corrupted software or firmware in control modules
  • Battery or power supply issues
  • Intermittent connection problems
  • Issues with 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. Other codes can provide context and help identify the root cause of the problem

  2. 2. Inspect Wiring and Connectors

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

  3. 3. Pay special attention to the connectors on the modules that communicate over the bus

  4. 4. Check for Short Circuits or Open Circuits

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

  5. 5. Check the resistance of the CAN bus lines (typically CAN High and CAN Low) to ensure they are within specifications

  6. 6. Test the Modules

    If possible, test the individual modules connected to the CAN bus. A malfunctioning module can disrupt communication across the network

  7. 7. Disconnect each module one at a time and see if the code clears or if communication is restored

  8. 8. Inspect the CAN Bus Termination Resistors

    Ensure that the CAN bus has the correct termination resistors (typically 120 ohms) at both ends of the bus. A missing or faulty resistor can cause communication issues

  9. 9. Check for Interference

    Look for any aftermarket devices or modifications that may interfere with the CAN bus communication, such as alarms, stereo systems, or other electronic devices

  10. 10. Update or Reprogram Modules

    In some cases, updating or reprogramming the vehicle's modules may resolve communication issues. Check with the manufacturer for any available updates

  11. 11. Perform a Network Test

    Some advanced scan tools can perform a network test to check the health of the CAN bus. This can help identify issues with specific modules or wiring

  12. 12. Clear Codes and Test Drive

    After performing the above checks and repairs, clear the trouble codes and take the vehicle for a test drive to see if the code returns

  13. 13. Consult a Professional

    If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or technician who specializes in automotive electronics and diagnostics.Conclusion Troubleshooting a U2535 code can be complex due to the nature of vehicle communication systems. Following these steps systematically can help identify and resolve the underlying issue. Always refer to the vehicle's service manual for specific information related to the make and model you are working on