B1871 – Passenger Air Bag Disable Module Fault

The ODBII code B1871 indicates a fault in the passenger airbag disable module, which may affect the proper functioning of the airbag system.

The severity of ODBII code B1871 is typically considered moderate to high.

Common Causes For: B1870 Lamp Air Bag Warning Indicator Circuit Short To Battery

• Faulty passenger airbag disable switch
• Wiring issues or damaged connectors
• Malfunctioning airbag control module
• Corrosion or poor connections in the airbag system
• Faulty sensors related to the passenger airbag system
• Software issues in the airbag control module
• Low battery voltage or electrical system problems

Common misdiagnosis for B1871 Passenger Air Bag Disable Module Fault

• Faulty airbag control module
• Defective passenger seat sensor
• Wiring issues or shorts in the airbag system
• Malfunctioning seat belt buckle switch
• Incorrectly installed or damaged passenger seat
• Software issues in the vehicle’s diagnostic system
• Faulty or corroded connectors in the airbag system

Common Troubleshooting Steps

When dealing with OBD-II code B1871, which indicates a “Passenger Air Bag Disable Module Fault,” it’s important to follow a systematic approach to troubleshoot the issue. Here are common troubleshooting steps:

• Check for Additional Codes: Use an OBD-II scanner to check for any other related trouble codes. This can provide more context and help identify if there are other issues affecting the airbag system.
• Inspect the Passenger Air Bag Disable Switch:
• Ensure that the switch is functioning properly. Check for any physical damage or wear.
• Verify that the switch is in the correct position (enabled/disabled) as per the vehicle’s requirements.
• Examine Wiring and Connectors:
• Inspect the wiring harness and connectors associated with the passenger airbag disable module. Look for signs of damage, corrosion, or loose connections.
• Pay special attention to any connectors that may have been disturbed during repairs or maintenance.
• Check the Airbag Control Module:
• Ensure that the airbag control module is functioning correctly. If there are issues with the module, it may need to be reprogrammed or replaced.
• Verify that the module is receiving power and ground.
• Inspect the Passenger Seat:
• Some vehicles have weight sensors in the passenger seat that determine whether the airbag should be enabled or disabled. Check for any issues with the seat sensor or its wiring.
• Ensure that there are no obstructions or foreign objects on the seat that could affect the sensor’s operation.
• Clear Codes and Test Drive:
• After performing the above checks and repairs, clear the trouble codes using the OBD-II scanner.
• Take the vehicle for a test drive to see if the code returns. Monitor the airbag system to ensure it is functioning correctly.
• Consult Technical Service Bulletins (TSBs):
• Check for any manufacturer-specific TSBs related to the B1871 code. There may be known issues or recalls that could provide additional guidance.
• Professional Diagnosis:
• If the issue persists after performing the above steps, consider seeking help from a professional mechanic or dealership. They may have specialized diagnostic tools and knowledge of the specific vehicle model. Always remember that airbag systems are critical for safety, and any repairs or diagnostics should be performed with caution. If you’re not comfortable working on these systems, it’s best to consult a professional.