B1604 – Lamp Anti-Theft Indicator Circuit Open
The ODBII code B1604 indicates that there is an open circuit in the lamp anti-theft indicator, which may prevent the indicator from functioning properly.
The severity of ODBII code B1604 is generally considered moderate.
Common Causes For: B1603 Lamp Anti-Theft Indicator Circuit Failure
- 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 misdiagnosis for B1604 Lamp Anti-Theft Indicator Circuit Open
- 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
Common Troubleshooting Steps
The OBD-II code B1604 indicates a problem with the anti-theft indicator circuit, specifically that the circuit is open. This can be related to the vehicle’s security system and may affect the operation of the anti-theft features. Here are some common troubleshooting steps to diagnose and resolve the issue:
- 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.
- 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.
- Visual Inspection of Wiring and Connectors:
- Inspect the wiring harness and connectors associated with the anti-theft system for any signs of damage, corrosion, or loose connections.
- Look for frayed wires, broken connectors, or any signs of wear that could cause an open circuit.
- Check Fuses: Locate and inspect the fuses related to the anti-theft system. Replace any blown fuses and check if the issue persists.
- Test the Anti-Theft Module: If applicable, test the anti-theft control module for proper operation. This may require specialized diagnostic equipment or tools.
- 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.
- 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.
- 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.
- 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.
- 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.