AutoCodesFord – B0004 Ford

B0004 Ford Code - Driver Knee Bolster Deployment Control

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 Knee Airbag, Driver Knee Airbag harness is open or shorted, Driver Knee Airbag 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
B0004 Ford indicates Driver Knee Bolster Deployment Control.
Common causes
Common causes include Faulty Driver Knee Airbag, Driver Knee Airbag harness is open or shorted, Driver Knee Airbag 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 14,054
How popular is this code, among other codes? Low
Table of contents Created and updated by William Orellana on Nov 18, 2024
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Code B0004 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 B0004 Ford - Driver Knee Bolster Deployment Control - AutoCodes.com
B0004 Ford Code - Driver Knee Bolster Deployment Control

What are the Possible Causes of the DTC B0004 Ford?

  • Faulty Driver Knee Airbag
  • Driver Knee Airbag harness is open or shorted
  • Driver Knee Airbag circuit poor electrical connection

How to Fix the DTC B0004 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 B0004 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 B0004 Ford code?

Need more information on how to fix the B0004 Ford code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B0004 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 B0004 Ford Code

1. What are the common symptoms of OBDII code B0004 for Ford related to the Driver Knee Bolster Deployment Control?

- Common symptoms include the airbag warning light illuminating on the dashboard and a potential non-deployment of the driver's knee bolster airbag during a collision.

2. What are the possible causes of OBDII code B0004 for Ford?

- The code B0004 can be triggered by a faulty driver knee bolster airbag module, damaged wiring harness, or a malfunction in the airbag system's control unit.

3. How can I diagnose the OBDII code B0004 in my Ford vehicle?

- Diagnosis typically involves using an OBDII scanner to retrieve the fault codes and then inspecting the driver knee bolster airbag system components for any visible damage or defects.

4. Can I drive my Ford with OBDII code B0004 present?

- It is recommended to address the issue promptly as driving with a fault in the driver knee bolster airbag system may compromise safety in the event of a collision.

5. What repair tips can help resolve OBDII code B0004 for Ford?

- Repairing the issue may involve replacing the driver knee bolster airbag module, repairing or replacing damaged wiring, and resetting the airbag system using a diagnostic tool.

6. Is it safe to attempt DIY repairs for OBDII code B0004 in my Ford?

- It is advisable to have the necessary knowledge and experience in handling airbag systems before attempting any DIY repairs, as incorrect procedures can pose safety risks.

7. How much does it cost to fix OBDII code B0004 in a Ford vehicle?

- The cost of fixing OBDII code B0004 can vary depending on the specific issue, but it may involve parts replacement, labor costs, and diagnostic fees, which can range from a few hundred to over a thousand dollars.

8. Can OBDII code B0004 be a false alarm in Ford vehicles?

- While rare, false alarms for OBDII code B0004 can occur due to intermittent electrical issues or sensor malfunctions, so it's recommended to have the system thoroughly inspected to rule out any actual faults.

9. Are there any recalls or technical service bulletins related to OBDII code B0004 for Ford vehicles?

- It's advisable to check with a Ford dealership or online databases for any recalls or technical service bulletins related to OBDII code B0004, as manufacturers sometimes issue repair instructions for known issues.

10. How can I prevent OBDII code B0004 from occurring in my Ford vehicle?

- Regular maintenance checks, including inspecting the airbag system components for wear or damage, can help prevent OBDII code B0004 from occurring. If any issues are detected, they should be addressed promptly.

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