B0004 — Driver Knee Bolster Deployment Control

What Does B0004 Mean?

B0004 is a diagnostic trouble code indicating: Driver Knee Bolster Deployment Control. This code relates to the body electrical system. The vehicle's computer detected a condition outside normal operating parameters and stored this code.

Symptoms of B0004

⚠️ Check Engine Light (MIL) illuminated
⚠️ Driver Knee Bolster Deployment Control not functioning as expected
⚠️ Related system may be in fail-safe mode
⚠️ Interior or exterior lighting malfunction

Common Causes

🔍 Faulty Driver Knee Bolster Deployment Control
🔍 Wiring or connector issue in Driver Knee Bolster Deployment Control circuit
🔍 Related mechanical or electrical fault
🔍 ECM/PCM issue (rare)

Frequently Asked Questions

What does B0004 mean?

B0004 indicates: Driver Knee Bolster Deployment Control. The vehicle's computer has detected that the Driver Knee Bolster Deployment Control is not operating within its expected parameters and stored this diagnostic trouble code.

Can I drive with code B0004?

Yes, B0004 is generally safe to drive with in the short term. However, it should still be addressed to pass emissions testing and prevent potential secondary issues.

How much does it cost to fix B0004?

Repair costs for B0004 typically range from $80 to $300, depending on the root cause. Simple wiring or connector repairs are on the lower end, while component replacement costs more. A proper diagnosis ($80–$150 at most shops) will identify the exact cause before committing to expensive parts.

What To Do Next

Possible Fixes

🔧 Inspect Driver Knee Bolster Deployment Control and related wiring
🔧 Replace faulty Driver Knee Bolster Deployment Control

1
Find your vehicle above
Click your make and model for real owner reports and common causes specific to your vehicle.
2
Check for recalls
Go to nhtsa.gov/recalls and enter your VIN. Free repairs if covered.
3
Get a professional diagnosis
A code alone doesn't identify the exact failed part. A diagnostic ($50–$150) pinpoints the root cause.

B0004: Driver Knee Bolster Deployment Control