WOMS
U code network Medium severity

U1105 Lost Communication with Vehicle Anti-Theft System (VATS) Module

The OBD2 code U1105 indicates that there is a lost communication issue with the Vehicle Anti-Theft System (VATS) module, which may affect the vehicle's security and starting functions

Definition

The OBD2 code U1105 indicates that there is a lost communication issue with the Vehicle Anti-Theft System (VATS) module, which may affect the vehicle's security and starting functions

Common causes

  • Faulty VATS module
  • Damaged wiring or connectors
  • Poor ground connection
  • Blown fuse
  • Malfunctioning ignition switch
  • Corroded terminals
  • Faulty key or key fob
  • Issues with the vehicle's PCM (Powertrain Control Module)

Common misdiagnoses

  • Faulty ignition switch
  • Bad wiring or connectors
  • Defective key or key fob
  • Malfunctioning body control module (BCM)
  • Issues with the engine control module (ECM)
  • Battery or charging system problems
  • Faulty anti-theft system components
  • Incorrectly programmed or cloned keys
  • Problems with the vehicle's immobilizer system
  • Software glitches in the vehicle's computer systems

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

    Visual Inspection: Check the wiring and connectors related to the VATS module for any signs of damage, corrosion, or loose connections

  3. 3. Connector Pins

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

  4. 4. Test the VATS Module

    If accessible, test the VATS module for proper operation. This may involve checking the power and ground connections to the module

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

  6. 6. Check for Communication Issues

    Use a scan tool to check if the VATS module is communicating with the vehicle’s network. If it is not, there may be a communication issue

  7. 7. Inspect the vehicle’s CAN (Controller Area Network) bus for faults. This may involve checking other modules for communication errors

  8. 8. Inspect the Fuses

    Check the fuses related to the VATS system and the vehicle’s electrical system. A blown fuse can interrupt communication

  9. 9. Look for Interference

    Ensure that there are no aftermarket devices or modifications that could interfere with the VATS system or its communication

  10. 10. Reset the System

    Clear the trouble codes using the OBD-II scanner and see if the code returns. Sometimes, a temporary glitch can cause communication issues

  11. 11. Check the Ignition Switch

    The ignition switch can sometimes cause issues with the VATS system. Ensure that it is functioning properly and making good contact

  12. 12. Consult Technical Service Bulletins (TSBs)

    Check for any TSBs related to the VATS system for your specific vehicle make and model. Manufacturers may have issued guidance on common issues

  13. 13. Professional Diagnosis

    If the issue persists after performing the above steps, it may be necessary to consult a professional mechanic or dealership for further diagnosis. They may have specialized tools and knowledge to address complex issues.1

  14. 14. Replace the VATS Module (if necessary)

    If all other troubleshooting steps have been exhausted and the VATS module is determined to be faulty, replacement may be necessary.Conclusion Always remember to take safety precautions when working on a vehicle's electrical system. If you're not comfortable performing these steps, it's advisable to seek help from a qualified technician