WOMS
U code network Medium severity

U1807 U1807: Data Bus Communication Fault

The OBD2 code U1807 indicates a data bus communication fault, meaning there is a problem with the communication between the vehicle's control modules over the data bus network

Definition

The OBD2 code U1807 indicates a data bus communication fault, meaning there is a problem with the communication between the vehicle's control modules over the data bus network

Common causes

  • Faulty wiring or connectors in the data bus system
  • Malfunctioning control modules
  • Poor ground connections
  • Corroded or damaged terminals
  • Interference from aftermarket devices
  • Software issues or incompatibility between modules
  • Low battery voltage or power supply issues
  • Faulty or damaged data bus communication lines

Common misdiagnoses

  • Faulty ABS module
  • Defective engine control module (ECM)
  • Malfunctioning transmission control module (TCM)
  • Bad wiring or connectors
  • Faulty body control module (BCM)
  • Issues with the CAN bus system
  • Defective sensors or actuators
  • Low battery voltage or poor ground connections

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 pinpoint the issue

  2. 2. Inspect the Wiring and Connectors

    Visual Inspection: Look for damaged, frayed, or corroded wiring and connectors related to the data bus

  3. 3. Connector Integrity

    Ensure that all connectors are securely attached and free of corrosion or dirt

  4. 4. Check the Data Bus

    Network Integrity: Use a multimeter to check the resistance of the data bus. A short circuit or open circuit can cause communication faults

  5. 5. Signal Quality

    If possible, use an oscilloscope to check the signal quality on the data bus lines

  6. 6. Inspect Modules

    Module Functionality: Check if any modules (like the ECM, BCM, ABS, etc.) are malfunctioning. A faulty module can disrupt communication

  7. 7. Reprogram or Reset Modules

    Sometimes, reprogramming or resetting the affected modules can resolve communication issues

  8. 8. Check for Ground Issues

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

  9. 9. Look for Interference

    Check for any aftermarket devices or modifications that may interfere with the vehicle's data bus communication

  10. 10. Perform a Network Test

    If available, use a scan tool capable of performing a network test to identify which module is not communicating properly

  11. 11. 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

  12. 12. Seek Professional Help

    If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or technician with experience in automotive electronics. By following these steps, you should be able to identify and resolve the underlying issue causing the U1807 code