AutoCodesToyota – B1921 Toyota

B1921 Toyota 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 Toyota 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 9,791
How popular is this code, among other codes? Low
Table of contents Created and updated by William Orellana on Jul 28, 2019
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Code B1921 Toyota 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 Toyota - Open In Rear Pretensioner Squib RH Circuit - AutoCodes.com
B1921 Toyota Code - Open In Rear Pretensioner Squib RH Circuit

What are the Possible Causes of the DTC B1921 Toyota?

  • 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 Toyota?

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 Toyota 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 Toyota code?

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

Need Help with the Code?

Get the B1921 Toyota 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 Toyota Code

1. What does the OBDII code B1921 mean on a Toyota?

B1921 indicates an open circuit in the right-hand (RH) rear pretensioner squib, which is part of the airbag system responsible for tightening the seatbelt during a collision.

2. What are the common symptoms of the B1921 code?

Symptoms may include the airbag warning light being illuminated on the dashboard and potential deactivation of the seatbelt pretensioner system.

3. What causes the B1921 code to appear?

Common causes include a damaged or disconnected pretensioner wiring harness, a faulty seatbelt pretensioner, corroded electrical connectors, or a malfunctioning airbag control module.

4. Is it safe to drive with the B1921 code active?

It is not recommended to drive with the B1921 code active, as the seatbelt pretensioner system may not function properly in the event of an accident, reducing occupant safety.

5. How is the B1921 code diagnosed?

A technician will use a scan tool to confirm the code, inspect the pretensioner wiring and connectors for damage, and perform resistance and continuity tests on the circuit.

6. Can a loose connection trigger the B1921 code?

Yes, a loose or corroded connection in the pretensioner wiring or connectors can trigger the B1921 code.

7. How can the B1921 code be fixed?

Repairs may involve reconnecting or replacing damaged wiring, cleaning or replacing corroded connectors, or replacing a faulty seatbelt pretensioner or airbag control module.

8. What tools are needed to repair the B1921 code?

Common tools include a diagnostic scan tool, a multimeter for electrical testing, and basic hand tools for accessing and repairing wiring or components.

9. Does the B1921 code require the airbag system to be reset?

Yes, after repairs are completed, the airbag system may need to be reset using a diagnostic scan tool to clear the code and turn off the warning light.

10. Can the B1921 code reappear after being fixed?

If the underlying issue, such as wiring damage or a faulty component, is not fully resolved, the B1921 code may reappear. Always ensure thorough diagnosis and repair.

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