AutoCodes – GMC – B0021 GMC

B0021 GMC 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 GMC 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 11,603

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

What does this mean?

What are the Possible Causes of the DTC B0021 GMC?

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 GMC?

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 GMC 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 GMC code?

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

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

Information for Specific GMC Models

B0021 2014 GMC Sierra — Passenger Seat Side Air Bag Deployment Loop
B0021 2015 GMC Sierra — Passenger Seat Side Air Bag Deployment Loop
B0021 2016 GMC Sierra — Passenger Seat Side Air Bag Deployment Loop
B0021 2017 GMC Sierra — Passenger Seat Side Air Bag Deployment Loop
B0021 2018 GMC Sierra — 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 GMC Code

1. What are the common symptoms of OBDII code B0021 GMC Passenger Seat Side Air Bag Deployment Loop?

The common symptoms include the airbag warning light illuminating on the dashboard and a diagnostic trouble code (DTC) B0021 being stored in the vehicle's system.

2. What are the possible causes of OBDII code B0021 GMC Passenger Seat Side Air Bag Deployment Loop?

The code B0021 typically indicates a fault in the passenger seat side airbag deployment loop circuit. Possible causes include wiring issues, a faulty airbag deployment loop, or a problem with the airbag control module.

3. How can I diagnose the OBDII code B0021 GMC Passenger Seat Side Air Bag Deployment Loop?

Diagnosing the B0021 code usually involves using a diagnostic scan tool to retrieve the fault code and then inspecting the passenger seat side airbag deployment loop circuit for any visible damage or loose connections.

4. Is it safe to drive with OBDII code B0021 GMC Passenger Seat Side Air Bag Deployment Loop?

It is recommended not to drive the vehicle if the airbag warning light is illuminated due to the potential safety risk of the passenger seat side airbag not deploying properly in the event of a collision.

5. How can I repair OBDII code B0021 GMC Passenger Seat Side Air Bag Deployment Loop?

Repairing the B0021 code may involve repairing or replacing damaged wiring in the airbag deployment loop circuit, replacing the passenger seat side airbag deployment loop itself, or reprogramming the airbag control module.

6. Can I reset the OBDII code B0021 GMC Passenger Seat Side Air Bag Deployment Loop without fixing the underlying issue?

Resetting the code without addressing the root cause will likely result in the code reappearing once the system detects the fault again. It is essential to diagnose and repair the issue to ensure the airbag system's proper functionality.

7. How much does it cost to repair OBDII code B0021 GMC Passenger Seat Side Air Bag Deployment Loop?

The cost of repairing the B0021 code can vary depending on the specific cause of the issue, the extent of the damage, and labor costs. It is recommended to consult a professional mechanic for an accurate estimate.

8. Can I fix OBDII code B0021 GMC Passenger Seat Side Air Bag Deployment Loop myself?

While diagnosing and repairing the B0021 code may be possible for experienced DIYers, working on airbag systems requires caution and knowledge due to safety concerns. It is advisable to seek professional help if you are unsure or inexperienced.

9. How long does it take to repair OBDII code B0021 GMC Passenger Seat Side Air Bag Deployment Loop?

The repair time for the B0021 code can vary depending on the exact issue and the availability of parts. Some repairs may be completed within a few hours, while more complex issues could take longer.

10. Will OBDII code B0021 GMC Passenger Seat Side Air Bag Deployment Loop affect my vehicle's overall safety?

Yes, the B0021 code indicates a potential problem with the passenger seat side airbag deployment loop, which can compromise the airbag system's effectiveness in a collision. It is crucial to address this issue promptly to ensure the safety of vehicle occupants.