WOMS
B code body Medium severity

B1604 Lamp Anti-Theft Indicator Circuit Open

The OBD2 code B1604 indicates that there is an open circuit in the lamp anti-theft indicator, which may prevent the indicator from functioning properly

Definition

The OBD2 code B1604 indicates that there is an open circuit in the lamp anti-theft indicator, which may prevent the indicator from functioning properly

Common causes

  • Faulty anti-theft module
  • Open circuit in the wiring
  • Damaged or corroded connectors
  • Faulty lamp or bulb
  • Malfunctioning body control module (BCM)
  • Blown fuse related to the anti-theft system
  • Poor ground connection

Common misdiagnoses

  • Faulty anti-theft module
  • Defective ignition switch
  • Bad wiring or connections
  • Malfunctioning body control module (BCM)
  • Faulty key fob or transponder
  • Dead battery in key fob
  • Issues with the vehicle's security system
  • Incorrectly programmed key or key replacement
  • Faulty dashboard indicator light
  • Problems with the vehicle's computer system

Troubleshooting steps

  1. 1. Check the Vehicle's Manual

    Refer to the vehicle's service manual for specific information about the anti-theft system and the wiring diagrams related to the indicator circuit

  2. 2. Inspect the Anti-Theft Indicator

    Check the anti-theft indicator light on the dashboard. Ensure that it is not damaged or burnt out. If the bulb is faulty, replace it

  3. 3. Visual Inspection of Wiring and Connectors

  4. 4. Inspect the wiring harness and connectors associated with the anti-theft system for any signs of damage, corrosion, or loose connections

  5. 5. Look for frayed wires, broken connectors, or any signs of wear that could cause an open circuit

  6. 6. Check Fuses

    Locate and inspect the fuses related to the anti-theft system. Replace any blown fuses and check if the issue persists

  7. 7. Test the Anti-Theft Module

    If applicable, test the anti-theft control module for proper operation. This may require specialized diagnostic equipment or tools

  8. 8. Scan for Additional Codes

    Use an OBD-II scanner to check for any other trouble codes that may be present. Other codes may provide additional context or indicate related issues

  9. 9. Perform a Continuity Test

    Using a multimeter, perform a continuity test on the wiring associated with the anti-theft indicator circuit. This will help identify any breaks in the circuit

  10. 10. Check Ground Connections

    Ensure that all ground connections related to the anti-theft system are secure and free of corrosion. A poor ground can cause circuit issues

  11. 11. Reset the System

    After performing repairs or inspections, clear the trouble codes using an OBD-II scanner and see if the code returns after a test drive

  12. 12. Consult a Professional

    If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or an automotive electrician who has experience with the specific vehicle's anti-theft system. By following these troubleshooting steps, you should be able to identify and resolve the issue related to the B1604 code