AutoCodes – Lincoln – B0021 Lincoln

B0021 Lincoln Code - Left Curtain Deployment Control 1

Quick Answer

The Restraints Control Module (RCM) monitors all deployable device and sensor circuits for a signal cross coupled (short) between circuits. Common causes include Faulty Driver Side Air Curtain, Driver Side Air Curtain harness is open or shorted, Driver Side Air Curtain 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 Lincoln indicates Left Curtain Deployment Control 1.
Common causes: Common causes include Faulty Driver Side Air Curtain, Driver Side Air Curtain harness is open or shorted, Driver Side Air Curtain 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 4,394

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
Cost to Diagnose
FAQs
Comments
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Code B0021 Lincoln Description

The Restraints Control Module (RCM) monitors all deployable device and sensor circuits for a signal cross coupled (short) between circuits. If the RCM detects a short between the circuits of one device and another device, it will store a DTC for each of the signal cross coupled faults in memory. The RCM sends a message to the Instrument Panel Cluster (IPC) to illuminate the air bag warning indicator. When a normal loop fault is present (one loop is either shorted to battery/ground, open circuit or low resistance), then signal cross coupled diagnostics will not be active. Once the normal loop fault is repaired, then the signal cross coupled diagnostics will resume.

OBDII Code B0021 Lincoln - Left Curtain Deployment Control 1 - AutoCodes.com — B0021 Lincoln Code - Left Curtain Deployment Control 1

What does this mean?

What are the Possible Causes of the DTC B0021 Lincoln?

Faulty Driver Side Air Curtain
Driver Side Air Curtain harness is open or shorted
Driver Side Air Curtain circuit poor electrical connection

How to Fix the DTC B0021 Lincoln?

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 B0021 Lincoln 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 Lincoln code?

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

Need Help with the Code?

Get the B0021 Lincoln 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 Lincoln Code

1. What are the common symptoms of OBDII code B0021 in a Lincoln related to the Left Curtain Deployment Control 1?

- Common symptoms include the airbag warning light illuminating on the dashboard and potential issues with the left side curtain airbag deployment.

2. What are the typical causes of OBDII code B0021 in a Lincoln?

- The code B0021 in a Lincoln typically indicates a fault with the left curtain airbag deployment control module, wiring issues, or a malfunction in the airbag system.

3. How can I diagnose OBDII code B0021 in my Lincoln?

- Diagnosing OBDII code B0021 involves using a professional OBDII scanner to read the code, inspecting the left curtain airbag deployment control module and related wiring for any damage or loose connections, and performing necessary tests to identify the root cause.

4. Can I drive my Lincoln with OBDII code B0021 present?

- It is not recommended to drive the vehicle with OBDII code B0021 present, as it indicates a potential issue with the left curtain airbag deployment system, which could compromise the safety of the vehicle in the event of a collision.

5. How can I repair OBDII code B0021 in my Lincoln?

- Repairing OBDII code B0021 may require replacing the left curtain airbag deployment control module, repairing or replacing damaged wiring, or addressing any other underlying issues causing the code to trigger.

6. Is it safe to reset the OBDII code B0021 in my Lincoln without fixing the underlying issue?

- It is not recommended to simply reset the OBDII code B0021 without addressing the underlying problem, as it could pose a safety risk in the event of an accident where the left curtain airbag deployment is needed.

7. Are there any DIY tips for troubleshooting OBDII code B0021 in a Lincoln?

- DIY tips for troubleshooting OBDII code B0021 include checking the fuses related to the airbag system, inspecting the wiring harness for damage, and ensuring all connections are secure before seeking professional help if needed.

8. How much does it typically cost to repair OBDII code B0021 in a Lincoln?

- The cost to repair OBDII code B0021 in a Lincoln can vary depending on the specific issue causing the code, but it may involve parts and labor costs ranging from a few hundred to over a thousand dollars.

9. Can weather conditions or rough driving cause OBDII code B0021 to trigger in a Lincoln?

- While weather conditions or rough driving may not directly cause OBDII code B0021 to trigger, they could exacerbate existing issues in the airbag system, leading to the code being detected during a diagnostic scan.

10. How often should I have the airbag system in my Lincoln inspected to prevent issues like OBDII code B0021?

- It is recommended to have the airbag system in your Lincoln inspected at least once a year or as per the manufacturer's recommended maintenance schedule to ensure all components are functioning correctly and to prevent issues like OBDII code B0021 from occurring.