AutoCodes – Generic – B1891

B1891 Code - Air Bag Tone Warning Indicator Circuit Short to Battery

Quick Answer

The connection between the Instrument Cluster Module and Restraints Control Module (RCM) is used to signal a chime if the primary air bag indicator is inoperative and another Supplemental Restraint System (SRS) fault exists. Common causes include Faulty Instrument Cluster Module, Instrument Cluster Module harness is open or shorted, Instrument Cluster Module circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: B1891 indicates Air Bag Tone Warning Indicator Circuit Short to Battery.
Common causes: Common causes include Faulty Instrument Cluster Module, Instrument Cluster Module harness is open or shorted, Instrument Cluster Module circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 11,638

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jul 12, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B1891 Description

The connection between the Instrument Cluster Module and Restraints Control Module (RCM) is used to signal a chime if the primary air bag indicator is inoperative and another Supplemental Restraint System (SRS) fault exists. The RCM monitors this connection to the Instrument Cluster Module. If the RCM detects a circuit failure on the connection to the cluster, it will store diagnostic trouble code (DTC) B1891 in memory and flash lamp on the air bag indicator.

OBDII Code B1891 - Air Bag Tone Warning Indicator Circuit Short to Battery - AutoCodes.com — B1891 Code - Air Bag Tone Warning Indicator Circuit Short to Battery

What does this mean?

What are the Possible Causes of the DTC B1891?

Faulty Instrument Cluster Module
Instrument Cluster Module harness is open or shorted
Instrument Cluster Module circuit poor electrical connection
Faulty Restraints Control Module (RCM)

How to Fix the DTC B1891?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the B1891 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the B1891 code?

Need more information on how to fix the B1891 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B1891 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

B1891 Ford — Air Bag Tone Warning Indicator Circuit Short to Battery
B1891 Lincoln — Air Bag Tone Warning Indicator Circuit Short to Battery
B1891 Mazda — Air Bag Tone Warning Indicator Circuit Short to Battery
B1891 Mercury — Air Bag Tone Warning Indicator Circuit Short to Battery

Precautions for SRS “AIR BAG” and “SEAT BELT PRE-TENSIONER” Service

Never probe the electrical connectors on air bag, side air curtain modules or seat belts.
Never disassemble or tamper with safety belt buckle/retractor pretensioners, adaptive load limiting retractors, safety belt inflators, or probe the electrical connectors.
Do not use electrical test equipment to check SRS circuits unless instructed to in this Service Manual.
Before servicing the SRS, turn ignition switch OFF, disconnect both battery cables and wait at least 3 minutes. For approximately 3 minutes after the cables are removed, it is still possible for the air bag and seat belt pre-tensioner to deploy. Therefore, do not work on any SRS connectors or wires until at least 3 minutes have passed.

Failure to follow this instruction may result in the accidental deployment of these modules, which increases the risk of serious personal injury or death.

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about B1891 Code

1. What are common symptoms of OBDII code B1891?

The common symptoms of OBDII code B1891 include the airbag warning light staying illuminated on the dashboard and the airbag system potentially not functioning properly.

2. What causes the OBDII code B1891 to be triggered?

The OBDII code B1891 is typically triggered when there is a short circuit to the battery in the airbag tone warning indicator circuit.

3. How can I diagnose the OBDII code B1891?

Diagnosing OBDII code B1891 involves using a scan tool to retrieve the code, inspecting the wiring and connectors in the airbag tone warning indicator circuit, and checking for any visible signs of damage.

4. What are some repair tips for fixing OBDII code B1891?

Repairing OBDII code B1891 may involve repairing or replacing damaged wiring or connectors in the airbag tone warning indicator circuit, ensuring proper connections, and clearing the code with a scan tool.

5. Is it safe to drive with OBDII code B1891 present?

It is not recommended to drive with OBDII code B1891 present, as it indicates a potential issue with the airbag system, which is crucial for safety in the event of a collision.

6. Can I reset the OBDII code B1891 without fixing the underlying issue?

While you can clear the code temporarily with a scan tool, it is important to address the underlying issue causing OBDII code B1891 to prevent it from reoccurring and ensure the proper functioning of the airbag system.

7. How much does it typically cost to repair OBDII code B1891?

The cost of repairing OBDII code B1891 can vary depending on the extent of the damage and the specific repairs needed, but it may range from a simple fix to more extensive repairs involving professional assistance.

8. Are there any safety precautions to consider when working on OBDII code B1891?

When working on OBDII code B1891 or any airbag-related issues, it is crucial to disconnect the vehicle's battery and wait for the system to fully discharge before beginning any repairs to prevent accidental airbag deployment.

9. Can a DIY enthusiast fix OBDII code B1891 at home?

Depending on the DIY enthusiast's skills and experience with automotive repairs, it may be possible to fix OBDII code B1891 at home by following proper diagnostic procedures and safety precautions.

10. How often does OBDII code B1891 occur in vehicles?

OBDII code B1891 can occur in vehicles equipped with airbag systems, and its frequency may vary depending on factors such as vehicle age, maintenance history, and driving conditions.