WOMS
U code network Medium severity

U1567 Communication Bus Off

The OBD2 code U1567 indicates a communication issue where the vehicle's communication bus is offline or not functioning properly, affecting data exchange between modules

Definition

The OBD2 code U1567 indicates a communication issue where the vehicle's communication bus is offline or not functioning properly, affecting data exchange between modules

Common causes

  • Faulty wiring or connectors in the communication bus
  • Malfunctioning control modules
  • Short circuits or open circuits in the communication lines
  • Corrupted software or firmware in the control modules
  • Electrical interference from other components
  • Low battery voltage or poor power supply
  • Faulty or damaged sensors connected to the bus

Common misdiagnoses

  • Faulty ABS module
  • Defective engine control module (ECM)
  • Malfunctioning body control module (BCM)
  • Wiring issues or shorts in the communication lines
  • Faulty sensors or actuators
  • Battery or charging system problems
  • Incorrectly installed aftermarket accessories
  • Software or firmware issues in modules

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 additional context for the issue

  2. 2. Inspect Wiring and Connectors

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

  3. 3. Pay special attention to the connectors at the control modules involved in the communication

  4. 4. Test the Communication Bus

    Use a multimeter or an oscilloscope to check the voltage levels on the CAN bus wires. The typical voltage levels should be around 2.5V to 2.7V when the bus is idle

  5. 5. Check for short circuits or open circuits in the communication lines

  6. 6. Check for Ground Issues

    Ensure that all control modules have a good ground connection. Poor grounding can lead to communication issues

  7. 7. Inspect Control Modules

    If the wiring and connections are good, the issue may lie with one of the control modules. Check for any signs of damage or failure

  8. 8. If possible, swap the suspected module with a known good one to see if the problem persists

  9. 9. Look for Interference

    Check for any aftermarket devices or modifications that may interfere with the communication bus, such as alarms, remote starters, or audio systems

  10. 10. Perform a Network Test

    Some advanced scan tools can perform a network test to check the integrity of the communication bus. This can help identify which module is causing the issue

  11. 11. Clear Codes and Test Drive

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

  12. 12. 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 automotive electronics and communication systems. By following these troubleshooting steps, you should be able to identify and resolve the underlying issue causing the U1567 code