AutoCodes – Generic – B0021:04

B0021:04 Code - Passenger Seat Side Air Bag Deployment Loop Open

Quick Answer

A Diagnostic Trouble Code (DTC) will be stored in non-volatile memory if a malfunction is detected. Common causes include Faulty Passenger Seat Side Air Bag, Passenger Seat Side Air Bag harness is open or shorted, Passenger Seat Side Air Bag 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: B0021:04 indicates Passenger Seat Side Air Bag Deployment Loop Open.
Common causes: Common causes include Faulty Passenger Seat Side Air Bag, Passenger Seat Side Air Bag harness is open or shorted, Passenger Seat Side Air Bag 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 718

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 Oct 09, 2022

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code B0021:04 Description

A Diagnostic Trouble Code (DTC) will be stored in non-volatile memory if a malfunction is detected. During a side or frontal crash of sufficient force, the inflatable restraint Sensing and Diagnostic Module (SDM) will allow current to flow through the deployment loop in order to deploy the passenger seat side air bag. The SDM performs continuous diagnostic tests on the deployment loops to check for proper circuit continuity and for shorts to ground or voltage. A shorting bar is used within the passenger seat side air bag connector which will short together both high and low circuits when the connector is disconnected. This will help to prevent unwanted deployment of the air bag during servicing. The Diagnostic Trouble Code (DTC) will be set when the air bag control circuit is open for 2 seconds.

OBDII Code B0021:04 - Passenger Seat Side Air Bag Deployment Loop Open - AutoCodes.com — B0021:04 Code - Passenger Seat Side Air Bag Deployment Loop Open

What does this mean?

What are the Possible Causes of the DTC B0021:04?

Faulty Passenger Seat Side Air Bag
Passenger Seat Side Air Bag harness is open or shorted
Passenger Seat Side Air Bag circuit poor electrical connection
Faulty Sensing and Diagnostic Module (SDM)

How to Fix the DTC B0021:04?

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 does this mean?

Code Tech Notes

B0021:01 Passenger Seat Side Air Bag Deployment Loop Short to Battery
B0021:02 Passenger Seat Side Air Bag Deployment Loop Short to Ground
B0021:04 Passenger Seat Side Air Bag Deployment Loop Open
B0021:0D Passenger Seat Side Air Bag Deployment Loop High Resistance
B0021:0E Passenger Seat Side Air Bag Deployment Loop Low Resistance

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the B0021:04 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 B0021:04 code?

Need more information on how to fix the B0021:04 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B0021:04 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 B0021:04 Code

1. What does the OBDII code B0021:04 mean?

The code B0021:04 indicates that there is an open circuit in the deployment loop of the passenger seat side airbag.

2. What are the common symptoms of a Passenger Seat Side Air Bag Deployment Loop Open issue?

Common symptoms include the airbag warning light illuminating on the dashboard and a potential inability of the passenger side airbag to deploy in the event of a collision.

3. What are some possible causes of the Passenger Seat Side Air Bag Deployment Loop Open code?

Potential causes of this code include damaged wiring, a faulty airbag deployment loop, a loose connection, or a malfunctioning airbag sensor.

4. How can I diagnose the issue causing the B0021:04 code?

Diagnosing the problem typically involves using a diagnostic scan tool to retrieve the fault codes, inspecting the wiring and connections related to the passenger seat side airbag, and testing the components for continuity and proper operation.

5. Can I still drive my vehicle with the B0021:04 code present?

It is not recommended to drive the vehicle with an unresolved airbag issue, as there is a risk that the passenger side airbag may not deploy properly in the event of an accident.

6. How can I repair a Passenger Seat Side Air Bag Deployment Loop Open problem?

Repairing this issue usually involves identifying and fixing the root cause, which may include repairing or replacing damaged wiring, fixing loose connections, or replacing faulty components like the airbag deployment loop or sensor.

7. Is it safe to reset the B0021:04 code without fixing the underlying problem?

Resetting the code without addressing the underlying issue is not recommended, as it may lead to continued airbag system malfunction and compromise passenger safety.

8. Are there any precautions I should take when working on the airbag system to resolve the B0021:04 code?

When working on the airbag system, it is crucial to disconnect the vehicle's battery and wait for a specified amount of time (as per manufacturer recommendations) to discharge any stored energy and prevent accidental airbag deployment.

9. How much does it typically cost to repair a Passenger Seat Side Air Bag Deployment Loop Open issue?

The cost of repairing this issue can vary depending on the specific cause, the extent of the damage, and whether any components need to be replaced. It is advisable to consult a professional mechanic for an accurate assessment.

10. Can I prevent the B0021:04 code from occurring in the future?

While some causes of the code may be due to wear and tear, regular maintenance checks, avoiding physical damage to the airbag system components, and addressing any warning signs promptly can help prevent the recurrence of this issue.