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Engine-Codes – Generic – B0004

B0004 Code - Driver Knee Bolster Deployment Control

Quick Answer

The B0004 diagnostic trouble code (DTC) relates to the Driver Knee Bolster Deployment Control system in the vehicle. Common causes include Faulty sensor detecting a collision, Wiring issues or damaged wiring harness, Malfunctioning control module. 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
B0004 indicates Driver Knee Bolster Deployment Control.
Common causes
Common causes include Faulty sensor detecting a collision, Wiring issues or damaged wiring harness, Malfunctioning control module.
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.
What is this?
Table of contents Created and updated by William Orellana on Sep 07, 2024
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Code B0004 Description

The B0004 diagnostic trouble code (DTC) relates to the Driver Knee Bolster Deployment Control system in the vehicle. This code typically indicates a malfunction or issue with the deployment control for the driver's knee bolster, which is a safety feature designed to protect the driver's knees in the event of a collision. The knee bolster is a cushioned panel located below the steering column, and it deploys during a crash to reduce the risk of leg injuries.

OBDII Code B0004 - Driver Knee Bolster Deployment Control
B0004 Code - Driver Knee Bolster Deployment Control

Common Causes of B0004

  1. Faulty sensor detecting a collision.
  2. Wiring issues or damaged wiring harness.
  3. Malfunctioning control module.
  4. Mechanical issue with the deployment mechanism.
  5. Water or moisture intrusion causing corrosion.

Symptoms of B0004

  1. Illumination of the airbag warning light on the dashboard.
  2. Inability of the knee bolster to deploy during a crash.
  3. An audible warning chime indicating a fault in the airbag system.
  4. Diagnostic trouble code B0004 stored in the vehicle's computer memory.

How to Fix B0004

  1. Begin by diagnosing the specific cause of the B0004 code using a professional automotive diagnostic tool.
  2. Inspect the sensor that detects a collision for any signs of damage or malfunction.
  3. Check the wiring harness for any breaks, frays, or corrosion, and repair or replace as needed.
  4. Test the control module for proper functionality and replace if faulty.
  5. Inspect the deployment mechanism for any mechanical issues and repair or replace as necessary.

Cost to Fix B0004

The cost of repairing a B0004 code related to the Driver Knee Bolster Deployment Control system can vary depending on the specific cause of the issue and the make and model of the vehicle. In general, the cost of parts for this repair can range from $100 to $500, while labor costs can range from $150 to $300. Overall, the total repair cost is likely to fall between $250 and $800. It's important to note that these are rough estimates, and actual costs may vary based on the factors mentioned above. Additionally, diagnostic time and labor rates can vary between auto repair shops, so it's advisable to obtain quotes from multiple sources before proceeding with the repair.

When is the Code Detected?

If the Restraints Control Module (RCM) detects a short between the driver knee air bag circuits and the circuits of another SRS component, it sets this Diagnostic Trouble Code (DTC) and the DTC of the corresponding SRS component.

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Code B0004 Information for Specific Makes

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 B0004 Code

1. What are common symptoms of OBDII code B0004?

- The common symptoms of OBDII code B0004 include the airbag warning light illuminating on the dashboard and a diagnostic trouble code related to the Driver Knee Bolster Deployment Control.

2. What does the OBDII code B0004 indicate?

- OBDII code B0004 indicates a problem with the Driver Knee Bolster Deployment Control system, which is responsible for deploying the knee airbag in the event of a collision.

3. What are possible causes of OBDII code B0004?

- Possible causes of OBDII code B0004 include a faulty Driver Knee Bolster Deployment Control module, wiring issues, or a problem with the knee airbag itself.

4. How can I diagnose the cause of OBDII code B0004?

- Diagnosing OBDII code B0004 involves using a diagnostic scanner to read the code, checking the wiring and connections to the Driver Knee Bolster Deployment Control module, and testing the functionality of the knee airbag.

5. What should I do if I encounter OBDII code B0004?

- If you encounter OBDII code B0004, it is recommended to have the issue diagnosed and repaired by a qualified technician to ensure the proper functioning of the Driver Knee Bolster Deployment Control system.

6. Can I drive my vehicle with OBDII code B0004?

- It is not recommended to drive your vehicle with OBDII code B0004 present, as it indicates a potential issue with the airbag system that could affect its ability to deploy in an accident.

7. How much does it cost to repair OBDII code B0004?

- The cost to repair OBDII code B0004 can vary depending on the underlying cause of the issue, with costs potentially ranging from a few hundred to a few thousand dollars.

8. Is OBDII code B0004 a common problem in vehicles?

- OBDII code B0004 is not as common as some other codes, but it can still occur in vehicles equipped with a Driver Knee Bolster Deployment Control system.

9. Can I reset OBDII code B0004 on my own?

- While you can clear the code using a diagnostic scanner, it is important to address the underlying issue causing OBDII code B0004 to prevent it from recurring.

10. How can I prevent OBDII code B0004 from appearing again?

- To prevent OBDII code B0004 from reappearing, it is essential to address any underlying issues promptly, perform regular maintenance on the airbag system, and avoid any physical damage to the knee airbag components.

Discuss the causes and fixes for B0004 OBDII Code

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  • Hi.
    Steering light keep flashing and I was given B0004. It's fiesta 2012

    Reply to Comment