B1891 – Air Bag Tone Warning Indicator Circuit Short to Battery

The ODBII code B1891 indicates a short circuit in the airbag tone warning indicator circuit, causing it to be continuously powered by the battery.

The severity of ODBII code B1891 is moderate to high.

Common Causes For: B1890 PAD Warning Lamp Circuit Short to Battery

• Shorted wiring or connectors
• Faulty airbag module
• Defective tone warning indicator
• Corroded or damaged connectors
• Malfunctioning body control module (BCM)
• Improper installation of aftermarket accessories
• Grounding issues in the airbag system

Common misdiagnosis for B1891 Air Bag Tone Warning Indicator Circuit Short to Battery

• Faulty airbag module
• Defective airbag sensor
• Wiring issues in the airbag system
• Malfunctioning clock spring
• Incorrectly installed or damaged airbag
• Faulty seat belt pretensioner
• Issues with the vehicle’s body control module (BCM)

Common Troubleshooting Steps

When dealing with OBD-II code B1891, which indicates a “Air Bag Tone Warning Indicator Circuit Short to Battery,” it’s important to follow a systematic approach to troubleshoot the issue. Here are common troubleshooting steps:

• Scan Tool Verification:
• Use an OBD-II scanner to confirm the presence of the B1891 code. Check for any other related codes that may provide additional context.
• Visual Inspection:
• Inspect the wiring and connectors associated with the airbag warning indicator circuit. Look for signs of damage, corrosion, or loose connections.
• Check the airbag module and any related components for physical damage.
• Check the Indicator Bulb:
• If applicable, check the airbag warning indicator bulb to ensure it is functioning correctly. A burnt-out bulb can sometimes cause issues.
• Test the Circuit:
• Use a multimeter to test the voltage and ground at the airbag warning indicator circuit. Ensure that the circuit is not shorted to battery voltage.
• Check for continuity in the circuit and look for any shorts to ground or battery.
• Inspect the Airbag Module:
• If the circuit tests are normal, inspect the airbag control module for faults. Ensure that it is properly connected and functioning.
• Check for Shorts:
• Look for any shorts in the wiring harness that could be causing the circuit to read battery voltage. This may involve tracing the wiring back to the source.
• Clear Codes and Test Drive:
• After performing repairs or adjustments, clear the trouble codes using the OBD-II scanner and take the vehicle for a test drive to see if the code returns.
• Consult Service Manual:
• Refer to the vehicle’s service manual for specific wiring diagrams and troubleshooting procedures related to the airbag system.
• Professional Diagnosis:
• If the issue persists after performing the above steps, consider seeking help from a professional technician who specializes in automotive electrical systems or airbag systems.
• Safety Precautions:
• Always take necessary safety precautions when working with airbag systems, as they can be dangerous if mishandled. Disconnect the battery and wait for a period before working on the airbag system. By following these steps, you should be able to identify and resolve the issue related to the B1891 code.