B1520 – Hood Switch Circuit Open

The ODBII code B1520 indicates that there is an open circuit in the hood switch, which is responsible for detecting whether the hood is closed or open.

The severity of ODBII code B1520 Hood Switch Circuit Open is generally considered moderate.

Common Causes For: B1519 Hood Switch Circuit Failure

• Faulty hood switch
• Damaged wiring or connectors
• Corroded terminals
• Open circuit in the wiring harness
• Poor ground connection
• Malfunctioning body control module (BCM)

Common misdiagnosis for B1520 Hood Switch Circuit Open

• Faulty hood latch
• Bad hood switch
• Wiring issues or shorts
• Body control module (BCM) failure
• Faulty alarm system
• Incorrectly installed aftermarket accessories
• Battery or power supply issues

Common Troubleshooting Steps

The OBD-II code B1520 indicates a problem with the hood switch circuit, specifically that the circuit is open. This can affect various systems in the vehicle, including the alarm system, interior lights, and others that rely on the hood switch for proper operation. Here are some common troubleshooting steps to diagnose and resolve the issue:

• Visual Inspection: **Check the Hood Switch: Locate the hood switch and inspect it for any visible damage, corrosion, or disconnection.
• **Wiring Inspection: Examine the wiring and connectors leading to the hood switch for fraying, breaks, or loose connections.
• Test the Hood Switch: **Multimeter Test: Use a multimeter to test the continuity of the hood switch. With the hood closed, the switch should show continuity (closed circuit). When the hood is open, it should show no continuity (open circuit).
• **Switch Operation: Manually operate the switch to ensure it is functioning correctly.
• Check for Faulty Connections: **Connector Inspection: Ensure that all connectors related to the hood switch are secure and free of corrosion.
• **Ground Connections: Check the ground connections for the hood switch circuit to ensure they are clean and secure.
• Inspect Related Components: **Body Control Module (BCM): If the hood switch is part of a larger system controlled by the BCM, check for any faults in the BCM.
• **Fuses: Check the relevant fuses associated with the hood switch circuit to ensure they are not blown.
• Scan for Additional Codes: **OBD-II Scanner: Use an OBD-II scanner to check for any additional trouble codes that may provide more context or indicate related issues.
• Clear Codes and Test Drive: **Clear Codes: After performing the above checks and repairs, clear the trouble codes using the OBD-II scanner.
• **Test Drive: Take the vehicle for a test drive to see if the code reappears.
• Consult Service Manual: If the issue persists, consult the vehicle’s service manual for specific troubleshooting steps related to the hood switch circuit for your make and model.
• Professional Diagnosis: If you are unable to resolve the issue, consider seeking help from a professional mechanic who can perform more advanced diagnostics. By following these steps, you should be able to identify and resolve the issue related to the B1520 code.