AutoCodesFord – B0021 Ford

B0021 Ford 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 Ford 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.
AI answers can be wrong. Verify repairs with testing. Open full chat
Code Popularity 17,465
How popular is this code, among other codes? Low
Table of contents Created and updated by William Orellana on Oct 09, 2022
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Code B0021 Ford 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 Ford - Left Curtain Deployment Control 1 - AutoCodes.com
B0021 Ford Code - Left Curtain Deployment Control 1

What are the Possible Causes of the DTC B0021 Ford?

  • 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 Ford?

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 Ford 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 Ford code?

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

Need Help with the Code?

Get the B0021 Ford 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 Ford Code

1. What does the OBDII code B0021 on a Ford indicate?

The code B0021 on a Ford signifies an issue with the Left Curtain Deployment Control circuit, indicating a problem in the deployment mechanism or circuitry of the left side curtain airbag.

2. What are common symptoms of code B0021 on a Ford?

Common symptoms include the airbag warning light being illuminated on the dashboard and the left side curtain airbag not deploying in the event of a collision.

3. What can cause the B0021 code to appear on a Ford?

Potential causes include a faulty left side curtain airbag module, damaged wiring or connectors in the airbag deployment circuit, or a malfunctioning airbag control unit.

4. How is the B0021 code diagnosed on a Ford?

Diagnosis involves using an OBDII scanner to read the fault codes, visually inspecting the wiring and connectors, and testing the left side curtain airbag module and control unit with specialized diagnostic tools.

5. What are the steps to fix the B0021 code on a Ford?

Repair steps typically include replacing or repairing the faulty left side curtain airbag module, repairing or replacing damaged wiring or connectors, and possibly reprogramming or replacing the airbag control unit.

6. Is it safe to drive a Ford with the B0021 code?

Driving with this code is not recommended as it involves a critical safety component. The left side curtain airbag may not deploy in an accident, increasing the risk of injury.

7. Can the B0021 code affect other systems in a Ford?

While the code specifically relates to the left curtain airbag, unresolved issues might affect the overall airbag system's readiness and functionality in a crash.

8. What tools are required to diagnose the B0021 code on a Ford?

Diagnosing this code requires an OBDII scanner, a digital multimeter, and possibly an oscilloscope to assess the electrical signals in the airbag deployment circuit.

9. How often is the B0021 code a result of electrical issues?

Electrical issues, such as faulty wiring or bad connections, are common causes of the B0021 code and should be thoroughly investigated during the diagnostic process.

Discuss the causes and fixes for B0021 Ford OBDII Code

  • I have a Hyundai Elentra Car Model 2012
    The airbag Sensiar is on .
    I made a Computer check
    And here the result with the Symbol
    DTC:B136100
    Description: Pretensioner Front-Driver Resistance too High.

  • B1361 HYUNDAI - Front-Driver Seat Belt Pretensioner Resistance Too High
    Read more: https://www.autocodes.com/b...

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