WOMS
U code network High severity

U2070 Control Module Communication Bus Off

The OBD2 code U2070 indicates a communication issue where a control module is not able to communicate on the vehicle's communication bus, often due to a fault in the module itself or a wiring issue

Definition

The OBD2 code U2070 indicates a communication issue where a control module is not able to communicate on the vehicle's communication bus, often due to a fault in the module itself or a wiring issue

Common causes

  • Faulty control module
  • Damaged wiring or connectors
  • Poor ground connections
  • Communication bus short circuit
  • Open circuit in the communication bus
  • Interference from aftermarket devices
  • Software issues or firmware corruption
  • Low battery voltage or power supply issues

Common misdiagnoses

  • Faulty control module
  • Wiring issues
  • Poor ground connections
  • Corrupted software/firmware
  • Faulty sensors
  • Battery or power supply problems
  • Intermittent connection issues
  • Other communication bus faults (e.g., CAN bus issues)

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

  2. 2. Inspect Wiring and Connectors

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

  3. 3. Pay special attention to the CAN bus wiring, which typically consists of a twisted pair of wires

  4. 4. Check Power and Ground

    Ensure that the affected control module has proper power and ground connections. Use a multimeter to verify voltage and ground continuity

  5. 5. Test the Control Module

    If possible, test the control module in question. This may involve bench testing or swapping with a known good module to see if the problem persists

  6. 6. Check for Short Circuits

    Inspect the wiring for any short circuits to ground or to other wires that could cause communication issues

  7. 7. Look for Intermittent Issues

    Sometimes, communication issues can be intermittent. Monitor the vehicle's performance and check for any patterns that may indicate when the issue occurs

  8. 8. Inspect Other Modules

    If multiple modules are involved, check the other modules on the CAN bus for faults. A fault in one module can affect communication across the entire bus

  9. 9. Check for Software Updates

    Verify if there are any software updates available for the control modules. Sometimes, manufacturers release updates to fix known communication issues

  10. 10. Scan for Bus Activity

    Use a scan tool capable of monitoring CAN bus activity to see if there are any abnormal signals or if the bus is functioning correctly

  11. 11. Clear Codes and Test Drive

    After performing checks and repairs, clear the trouble codes and take the vehicle for a test drive to see if the code returns.1

  12. 12. Seek Professional Help

    If the issue persists after performing these steps, consider seeking help from a professional mechanic or automotive technician who has experience with CAN bus systems. By following these steps, you should be able to identify and resolve the underlying issue causing the U2070 code