WOMS
U code network Medium severity

U1699 Manufacturer Specific Communication Bus Fault

The OBD2 code U1699 indicates a fault in the manufacturer-specific communication bus, suggesting a communication issue between modules in the vehicle's network

Definition

The OBD2 code U1699 indicates a fault in the manufacturer-specific communication bus, suggesting a communication issue between modules in the vehicle's network

Common causes

  • Faulty wiring or connectors in the communication bus
  • Malfunctioning control modules
  • Poor ground connections
  • Interference from aftermarket devices
  • Corroded or damaged pins in connectors
  • Software issues or bugs in the control modules
  • Low battery voltage or power supply issues
  • Faulty or damaged communication bus transceiver

Common misdiagnoses

  • Faulty wiring or connectors
  • Defective control modules
  • Communication issues with other modules
  • Battery or power supply problems
  • Software or firmware issues
  • Grounding problems
  • Intermittent faults in the communication bus
  • Incorrectly configured or programmed modules

Troubleshooting steps

  1. 1. Check for Other Codes

    Use an OBD-II scanner to check for any additional trouble codes. Sometimes, U1699 may be accompanied by other codes that can provide more context about the issue

  2. 2. Inspect Wiring and Connectors

  3. 3. Visually inspect the wiring and connectors associated with the communication bus. Look for signs of damage, corrosion, or loose connections

  4. 4. Pay special attention to the connectors on the modules that are part of the communication network

  5. 5. Check for Short Circuits

  6. 6. Use a multimeter to check for short circuits in the communication lines. Ensure that there are no unintended connections between wires that could cause interference

  7. 7. Test the Modules

  8. 8. If you suspect a specific module is causing the issue, you can test it by disconnecting it and checking if the code persists. If the code goes away, the module may be faulty

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

  10. 10. Inspect the Communication Bus

  11. 11. Use a scan tool that can monitor live data to check the communication status of the modules on the bus. Look for any modules that are not responding or showing unusual behavior

  12. 12. Check the resistance of the communication lines to ensure they are within specifications

  13. 13. Check Power and Ground

  14. 14. Ensure that all modules on the communication bus have proper power and ground connections. A weak or intermittent power supply can cause communication issues

  15. 15. Update Software/Firmware

  16. 16. Check if there are any software or firmware updates available for the vehicle's modules. Sometimes, communication issues can be resolved with an update

  17. 17. Clear Codes and Test Drive

  18. 18. After performing any repairs or adjustments, clear the trouble codes and take the vehicle for a test drive to see if the code returns

  19. 19. Consult Manufacturer Documentation

  20. 20. Since U1699 is manufacturer-specific, consult the vehicle's service manual or technical documentation for any specific troubleshooting steps or known issues related to this code

  21. 21. Seek Professional Help

  22. 22. 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 make and model of the vehicle. By following these steps, you should be able to identify and resolve the underlying issue causing the U1699 code