AutoCodes – Generic – B0021

B0021 Code - Passenger Seat Side Air Bag Deployment Loop

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 indicates Passenger Seat Side Air Bag Deployment Loop.
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 30,593

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 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.

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

What does this mean?

What are the Possible Causes of the DTC B0021?

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?

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 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 code?

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

Need Help with the Code?

Get the B0021 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

B0021 Buick — Passenger Seat Side Air Bag Deployment Loop
B0021 Cadillac — Passenger Seat Side Air Bag Deployment Loop
B0021 Chevrolet — Passenger Seat Side Air Bag Deployment Loop
B0021 Ford — Left Curtain Deployment Control 1
B0021 GMC — Passenger Seat Side Air Bag Deployment Loop
B0021 Lincoln — Left Curtain Deployment Control 1
B0021 Mercury — Left Curtain Deployment Control 1
B0021 Pontiac — Passenger Seat Side Air Bag Deployment Loop
B0021 Saturn — Passenger Seat Side Air Bag Deployment Loop

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 Code

1. What are common symptoms of an OBDII code B0021 related to the passenger seat side air bag deployment loop?

The common symptoms include the airbag warning light illuminating on the dashboard and a corresponding diagnostic trouble code (DTC) being stored in the vehicle's computer.

2. What could cause the OBDII code B0021 for the passenger seat side air bag deployment loop?

The code B0021 is typically triggered by a fault in the wiring, connectors, or components related to the passenger seat side airbag deployment loop, such as a short circuit or open circuit.

3. How can I diagnose the OBDII code B0021 for the passenger seat side air bag deployment loop?

Diagnosing this code often involves using a scan tool to retrieve the specific fault code, conducting visual inspections of the wiring and connectors, and performing resistance tests on the components in the deployment loop.

4. Is it safe to drive with an OBDII code B0021 related to the passenger seat side air bag deployment loop?

It is not recommended to drive the vehicle with this code present, as it indicates a potential issue with the airbag system, which could affect its functionality in the event of a collision.

5. Can I reset the OBDII code B0021 for the passenger seat side air bag deployment loop myself?

While you can clear the code with a scan tool, it is important to address the underlying issue causing the fault to prevent the code from returning and ensure the airbag system is functioning properly.

6. How much does it typically cost to repair an OBDII code B0021 for the passenger seat side air bag deployment loop?

The cost of repairs can vary depending on the specific cause of the fault, but it may involve replacing damaged wiring, connectors, or components in the passenger seat airbag deployment loop.

7. Are there any common DIY repair tips for fixing the OBDII code B0021 related to the passenger seat side air bag deployment loop?

While some basic visual inspections and wiring checks can be done by DIY enthusiasts, diagnosing and repairing the specific cause of the code may require professional expertise and specialized tools.

8. What are the potential risks of ignoring the OBDII code B0021 for the passenger seat side air bag deployment loop?

Ignoring this code can pose a safety risk, as a malfunctioning airbag system may not deploy properly in the event of a collision, potentially leading to increased injuries for occupants.

9. Can a faulty sensor trigger the OBDII code B0021 for the passenger seat side air bag deployment loop?

Yes, a faulty sensor related to the passenger seat side airbag deployment loop, such as a seat position sensor, could potentially trigger the B0021 code if it is not functioning correctly.

10. How long does it typically take to repair an OBDII code B0021 for the passenger seat side air bag deployment loop?

The repair time can vary based on the specific cause of the fault and the availability of parts, but it is advisable to have the issue addressed promptly by a qualified technician to ensure the airbag system's reliability.