WOMS
U code network High severity

U0072 Vehicle Communication Bus E (-) shorted to Bus E (+)

The OBD2 code U0072 indicates a communication issue where the Vehicle Communication Bus E negative line is shorted to the positive line, potentially causing problems in data transmission between modules

Definition

The OBD2 code U0072 indicates a communication issue where the Vehicle Communication Bus E negative line is shorted to the positive line, potentially causing problems in data transmission 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
  • Software issues or bugs in control modules

Common misdiagnoses

  • Faulty ECU (Engine Control Unit)
  • Faulty wiring or connectors
  • Faulty CAN bus module
  • Shorted wiring harness
  • Faulty sensors
  • Power supply issues
  • Grounding problems
  • Incorrectly configured aftermarket accessories

Troubleshooting steps

  1. 1. Check for Additional Codes

    Use an OBD-II scanner to check for any other related trouble codes. This can provide more context about the issue and help identify which systems may be affected

  2. 2. Inspect Wiring and Connectors

    Visually inspect the wiring harnesses and connectors associated with Bus E. Look for signs of damage, such as frayed wires, corrosion, or loose connections

  3. 3. Pay special attention to areas where the wiring may be exposed to heat, moisture, or physical wear

  4. 4. Check for Short Circuits

    Use a multimeter to check for continuity between the Bus E (-) and Bus E (+) wires. If there is continuity, it indicates a short circuit

  5. 5. Inspect the wiring for any points where the wires may be pinched or touching each other

  6. 6. Test the ECUs

    If the wiring appears to be in good condition, test the ECUs connected to Bus E. A malfunctioning ECU can sometimes cause communication issues

  7. 7. Disconnect the suspected ECU and see if the code clears. If it does, the ECU may need to be repaired or replaced

  8. 8. Check for Ground Issues

    Ensure that all ground connections related to the communication bus are secure and free of corrosion. Poor grounding can lead to communication problems

  9. 9. Inspect the Communication Bus

    If applicable, check the termination resistors on the communication bus. A missing or faulty resistor can cause communication issues

  10. 10. Ensure that the bus is properly terminated at both ends

  11. 11. Scan Tool Communication

    Use a professional scan tool to monitor the communication on the bus. This can help identify if specific modules are not responding or if there are communication errors

  12. 12. Look for Environmental Factors

    Consider any recent changes or repairs made to the vehicle that could have affected the communication bus, such as bodywork, electrical repairs, or component replacements

  13. 13. Perform a System Reset

    After addressing any identified issues, clear the trouble codes and perform a system reset. Then, take the vehicle for a test drive to see if the code returns

  14. 14. Consult Technical Service Bulletins (TSBs)

    Check for any manufacturer-specific TSBs related to the U0072 code or communication issues. There may be known fixes or updates available.1

  15. 15. Seek Professional Help

    If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or automotive technician with experience in vehicle communication systems. By following these troubleshooting steps, you can systematically identify and resolve the underlying issue causing the U0072 code