AutoCodes – Lexus – B1921 Lexus

B1921 Lexus Code - Open In Rear Pretensioner Squib RH Circuit

Quick Answer

The Rear Pretensioner Squib Right (RH) Circuit consists of the Center Airbag Sensor Assembly and the Rear Seat Outer Belt Assembly Right (RH). Common causes include Faulty Rear Seat Outer Belt Assembly Right (RH) (Rear Pretensioner Squib RH), Rear Seat Outer Belt Assembly Right (RH) harness is open or shorted, Rear Seat Outer Belt Assembly Right (RH) 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: B1921 Lexus indicates Open In Rear Pretensioner Squib RH Circuit.
Common causes: Common causes include Faulty Rear Seat Outer Belt Assembly Right (RH) (Rear Pretensioner Squib RH), Rear Seat Outer Belt Assembly Right (RH) harness is open or shorted, Rear Seat Outer Belt Assembly Right (RH) 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 8,010

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 28, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B1921 Lexus Description

The Rear Pretensioner Squib Right (RH) Circuit consists of the Center Airbag Sensor Assembly and the Rear Seat Outer Belt Assembly Right (RH). This circuit instructs the Supplemental Restraint System (SRS) to deploy when deployment conditions are met. The Diagnostic Trouble Code (DTC) is stored when a malfunction is detected in the Rear Pretensioner Squib RH Circuit.

OBDII Code B1921 Lexus - Open In Rear Pretensioner Squib RH Circuit - AutoCodes.com — B1921 Lexus Code - Open In Rear Pretensioner Squib RH Circuit

What does this mean?

What are the Possible Causes of the DTC B1921 Lexus?

Faulty Rear Seat Outer Belt Assembly Right (RH) (Rear Pretensioner Squib RH)
Rear Seat Outer Belt Assembly Right (RH) harness is open or shorted
Rear Seat Outer Belt Assembly Right (RH) circuit poor electrical connection
Faulty Center Airbag Sensor Assembly

How to Fix the DTC B1921 Lexus?

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 B1921 Lexus 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 B1921 Lexus code?

Need more information on how to fix the B1921 Lexus code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B1921 Lexus code diagnosed by a professional: Find a repair shop in your area

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 B1921 Lexus Code

1. What are the common symptoms of OBDII code B1921 in a Lexus related to the Rear Pretensioner Squib RH Circuit?

The common symptoms include the airbag warning light illuminating on the dashboard and a potential failure of the right rear seatbelt pretensioner.

2. What are the possible causes of OBDII code B1921 in a Lexus?

The code B1921 typically indicates an open circuit in the rear pretensioner squib RH, which could be caused by damaged wiring, a faulty pretensioner squib, or a poor electrical connection.

3. How can I diagnose the issue related to OBDII code B1921 in my Lexus?

To diagnose the problem, you can use a diagnostic scanner to read the fault codes, visually inspect the wiring and connections of the rear pretensioner squib RH, and perform continuity tests to identify any open circuits.

4. Can I continue driving my Lexus with OBDII code B1921 present?

It is not recommended to drive the vehicle with the airbag warning light on, as it indicates a potential issue with the airbag system, which may affect its functionality in the event of a collision.

5. How can I reset the OBDII code B1921 in my Lexus after repairing the issue?

Once you have fixed the open circuit in the rear pretensioner squib RH circuit, you can reset the fault codes using a diagnostic scanner or by disconnecting the car battery for a few minutes.

6. Are there any safety precautions to consider when working on the rear pretensioner squib RH circuit in a Lexus?

When working on the airbag system, always disconnect the car battery and wait for at least 10 minutes before starting any repairs to prevent accidental airbag deployment.

7. Can I repair the OBDII code B1921 issue in my Lexus by myself, or do I need professional help?

While some DIY enthusiasts may be able to diagnose and repair the open circuit issue, it is recommended to seek professional help, especially when dealing with the airbag system, due to safety concerns.

8. What is the typical cost to repair OBDII code B1921 in a Lexus at a dealership or auto repair shop?

The cost of repairing OBDII code B1921 can vary depending on the extent of the issue, but it may involve replacing the rear pretensioner squib RH or repairing the wiring, which could range from a few hundred to over a thousand dollars.

9. Is it necessary to replace the rear pretensioner squib RH if OBDII code B1921 is triggered in my Lexus?

If the issue is solely due to an open circuit in the wiring and the pretensioner squib is functioning properly, you may only need to repair the wiring and reset the fault code without replacing the squib.

10. How long does it take to repair OBDII code B1921 in a Lexus?

The repair time for OBDII code B1921 can vary depending on the extent of the issue and the expertise of the technician, but it may take a few hours to a full day to diagnose, repair, and reset the fault code.