WOMS
U code network High severity

U0063 Vehicle Communication Bus D (-) shorted to Bus D (+)

The OBD2 code U0063 indicates a communication issue where the negative line of the vehicle communication bus D is shorted to the positive line, potentially causing data transmission problems between modules

Definition

The OBD2 code U0063 indicates a communication issue where the negative line of the vehicle communication bus D is shorted to the positive line, potentially causing data transmission problems between modules

Common causes

  • Faulty wiring or connectors
  • Short circuit in the communication bus
  • Damaged or corroded connectors
  • Malfunctioning control modules
  • Poor ground connections
  • Interference from aftermarket devices
  • Faulty or damaged sensors on the bus
  • Software issues in control modules

Common misdiagnoses

  • Faulty ABS module
  • Defective engine control module (ECM)
  • Malfunctioning transmission control module (TCM)
  • Wiring harness issues
  • Shorted or damaged connectors
  • Faulty body control module (BCM)
  • Incorrectly installed aftermarket accessories
  • Powertrain control module (PCM) issues
  • Battery or charging system problems
  • Grounding issues

Troubleshooting steps

  1. 1. Check for Additional Codes

    Start by scanning the vehicle for any other diagnostic trouble codes (DTCs). This can provide more context about the issue and help identify if other systems are affected

  2. 2. Inspect Wiring and Connectors

  3. 3. Visually inspect the wiring harness and connectors associated with Bus D for any signs of damage, such as fraying, corrosion, or loose connections

  4. 4. Look for pinched or chafed wires that could cause a short circuit

  5. 5. Test the Bus Voltage

  6. 6. Use a multimeter to measure the voltage on the Bus D lines. You should see a specific voltage range (typically around 2.5V to 3.5V for CAN systems) when the vehicle is on. If the voltage is too low or too high, it may indicate a short

  7. 7. Check for Shorts

  8. 8. With the multimeter, check for continuity between the Bus D (+) and Bus D (-) wires. There should be no continuity (infinite resistance) between these two lines. If there is continuity, it indicates a short circuit

  9. 9. Inspect Modules on the Bus

  10. 10. Identify all modules connected to Bus D. Disconnect each module one at a time and check if the code clears or if the short is still present. This can help isolate the faulty module

  11. 11. Check for Ground Issues

  12. 12. Ensure that all ground connections related to the communication bus are secure and free of corrosion. A poor ground can cause communication issues

  13. 13. Look for Interference

  14. 14. Check for any aftermarket devices or modifications that may interfere with the communication bus. This includes alarm systems, stereo systems, or other electronic devices

  15. 15. Use a Scan Tool

  16. 16. Utilize a professional scan tool to monitor the communication on Bus D. This can help identify if specific modules are not responding or if there are communication errors

  17. 17. Repair or Replace Faulty Components

  18. 18. If you identify damaged wiring, connectors, or modules, repair or replace them as necessary

  19. 19. Clear Codes and Test Drive

  20. 20. After making repairs, clear the codes and take the vehicle for a test drive to see if the issue reoccurs. 1

  21. 21. If the problem persists, refer to the vehicle's service manual for specific diagnostic procedures related to the communication bus and any manufacturer-specific troubleshooting steps. If you are not comfortable performing these steps or if the issue remains unresolved, it may be best to consult a professional mechanic or technician with experience in automotive electrical systems