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U code network Medium severity

U1885 U1885: "Data Bus Communication Failure

The OBD2 code U1885 indicates a "Data Bus Communication Failure," meaning there is a problem with the communication between various electronic control units (ECUs) in the vehicle's network

Definition

The OBD2 code U1885 indicates a "Data Bus Communication Failure," meaning there is a problem with the communication between various electronic control units (ECUs) in the vehicle's network

Common causes

  • Faulty wiring or connectors
  • Malfunctioning control modules
  • Poor ground connections
  • Corroded or damaged terminals
  • Intermittent electrical connections
  • Software issues or bugs in control modules
  • Low battery voltage or weak battery
  • Faulty or damaged data bus (CAN bus) components
  • Aftermarket modifications or installations affecting communication
  • Environmental factors (moisture, temperature extremes) affecting connections

Common misdiagnoses

  • Faulty ABS module
  • Defective engine control module (ECM)
  • Malfunctioning body control module (BCM)
  • Wiring issues or shorts
  • Bad ground connections
  • Faulty sensors
  • Communication issues with other modules
  • Battery or charging system problems

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 communication failure

  2. 2. Inspect the Wiring and Connectors

    Visually inspect the wiring harnesses and connectors associated with the affected modules. Look for signs of damage, corrosion, or loose connections

  3. 3. Pay special attention to the connectors for the modules that are part of the data bus

  4. 4. Test the Modules

    Identify which modules are involved in the communication network. Common modules include the Engine Control Module (ECM), Transmission Control Module (TCM), Body Control Module (BCM), and others

  5. 5. Check if the affected modules are functioning properly. You may need to perform a module-specific diagnostic test

  6. 6. Check the Data Bus

    Use a multimeter or an oscilloscope to check the data bus lines (CAN, LIN, etc.) for proper voltage levels and signal integrity

  7. 7. Look for short circuits, open circuits, or excessive resistance in the data bus wiring

  8. 8. Inspect for Interference

    Ensure that there are no aftermarket devices or modifications that could be interfering with the data bus communication

  9. 9. Remove any non-factory accessories temporarily to see if the issue resolves

  10. 10. Check Power and Ground

    Verify that all modules have proper power and ground connections. A weak ground or insufficient power supply can lead to communication failures

  11. 11. Perform a Network Test

    Some advanced scan tools can perform a network test to check the communication between modules. This can help identify which module is not responding

  12. 12. Reset the Codes

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

  13. 13. Consult Technical Service Bulletins (TSBs)

    Check for any TSBs related to the specific make and model of the vehicle. Manufacturers may have issued guidance on common issues related to data bus communication

  14. 14. Seek Professional Help

    If the issue persists after performing the above steps, it may be necessary to consult a professional mechanic or technician who has experience with the specific vehicle and its systems. By following these steps, you should be able to identify and resolve the underlying issue causing the U1885 code