WOMS
U code network Medium severity

U2170 U2170: "Control Module Communication Line Fault

The OBD2 code U2170 indicates a fault in the communication line between control modules in a vehicle, suggesting that one or more modules are unable to communicate properly with each other

Definition

The OBD2 code U2170 indicates a fault in the communication line between control modules in a vehicle, suggesting that one or more modules are unable to communicate properly with each other

Common causes

  • Faulty wiring or connectors
  • Short circuit in communication lines
  • Open circuit in communication lines
  • Malfunctioning control module
  • Corroded connectors
  • Poor ground connection
  • Interference from aftermarket devices
  • Software issues or bugs in control modules
  • Low battery voltage or power supply issues
  • Faulty or damaged communication bus (CAN bus)

Common misdiagnoses

  • Faulty control module
  • Wiring issues
  • Poor ground connections
  • Corroded connectors
  • Faulty communication bus (CAN bus) issues
  • Software glitches or updates needed
  • Battery or power supply problems
  • Intermittent faults in other modules

Troubleshooting steps

  1. 1. Check for Additional Codes

    Use an OBD-II scanner to check for any other trouble codes that may be present. Sometimes, multiple codes can provide more context for the issue

  2. 2. Inspect Wiring and Connectors

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

  4. 4. Pay special attention to the communication lines (CAN bus lines) between modules

  5. 5. Check for Short Circuits

  6. 6. Use a multimeter to check for short circuits in the communication lines. Ensure that the resistance is within the expected range

  7. 7. Check for continuity between the modules to ensure that the communication lines are intact

  8. 8. Test Control Modules

  9. 9. If you suspect a specific control module is faulty, you can test it by swapping it with a known good module (if available) or using a diagnostic tool to check its functionality

  10. 10. Ensure that the module is receiving power and ground

  11. 11. Inspect the CAN Bus

  12. 12. If your vehicle uses a CAN bus system, check the bus for proper voltage levels. The typical voltage levels should be around 2.5V to 2.8V when the system is idle

  13. 13. Look for any devices that may be interfering with the communication, such as aftermarket accessories

  14. 14. Check for Software Updates

  15. 15. Sometimes, control modules may require software updates to function correctly. Check with the manufacturer for any available updates

  16. 16. Clear Codes and Test Drive

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

  18. 18. Consult Technical Service Bulletins (TSBs)

  19. 19. Check for any TSBs related to the U2170 code for your specific vehicle make and model. Manufacturers may have specific recommendations or known issues

  20. 20. Professional Diagnosis

  21. 21. If the issue persists after performing the above steps, it may be necessary to consult a professional mechanic or technician who has access to advanced diagnostic tools and equipment. By following these steps, you should be able to identify and resolve the underlying issue causing the U2170 code