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U0118 Lost Communication With Fuel Additive Control Module

The OBD2 code U0118 indicates a loss of communication with the fuel additive control module, which may affect the operation of the fuel system and related components

Definition

The OBD2 code U0118 indicates a loss of communication with the fuel additive control module, which may affect the operation of the fuel system and related components

Common causes

  • Faulty Fuel Additive Control Module
  • Damaged wiring or connectors
  • Poor electrical connections
  • Failed communication network (CAN bus issues)
  • Blown fuses
  • Software or firmware issues
  • Corrosion in connectors or terminals
  • Short circuits in the wiring harness

Common misdiagnoses

  • Faulty fuel additive control module
  • Wiring issues or damaged connectors
  • Faulty engine control module (ECM)
  • Incorrectly diagnosed fuel system issues
  • Problems with the fuel pump or fuel delivery system
  • Issues with the vehicle's communication network (CAN bus)
  • Faulty sensors related to fuel system operation
  • Battery or power supply issues affecting module communication

Troubleshooting steps

  1. 1. Check for Other Codes

    Use an OBD-II scanner to check for any additional trouble codes. Sometimes, multiple codes can provide more context about the issue

  2. 2. Inspect the Wiring and Connectors

    Visual Inspection: Check the wiring harness and connectors related to the Fuel Additive Control Module for any signs of damage, corrosion, or loose connections

  3. 3. Connector Pins

    Ensure that the pins in the connectors are not bent, corroded, or damaged

  4. 4. Test the Fuel Additive Control Module

    If accessible, test the Fuel Additive Control Module for proper operation. This may involve checking the module's power and ground connections

  5. 5. Use a multimeter to verify that the module is receiving the correct voltage and ground

  6. 6. Check for Communication Issues

    CAN Bus Communication: Since U0118 is a communication-related code, check the CAN bus for proper operation. Use a scan tool to monitor communication between modules

  7. 7. Wiring Issues

    Look for any shorts or opens in the communication lines (CAN High and CAN Low)

  8. 8. Inspect the Fuses

    Check the vehicle’s fuse box for any blown fuses that may affect the Fuel Additive Control Module or related systems

  9. 9. Perform a Module Reset

    Sometimes, resetting the module can clear temporary communication issues. Disconnect the battery for a few minutes, then reconnect it and see if the code returns

  10. 10. Update or Reprogram the Module

    If the module is not functioning correctly, it may need to be reprogrammed or updated. Check with the manufacturer for any available software updates

  11. 11. Check for Environmental Factors

    Ensure that there are no environmental factors affecting the module, such as moisture or extreme temperatures

  12. 12. Consult Technical Service Bulletins (TSBs)

    Look for any TSBs related to the specific make and model of your vehicle. Manufacturers may have issued guidance on common issues related to the Fuel Additive Control Module

  13. 13. 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 your vehicle's specific systems.Conclusion By following these troubleshooting steps, you can systematically identify and address the cause of the U0118 code. Always refer to the vehicle's service manual for specific procedures and specifications related to your vehicle model