P004C — Turbocharger/Supercharger Boost Control B Circuit Low

What Does P004C Mean?

P004C is a diagnostic trouble code indicating: Turbocharger/Supercharger Boost Control B Circuit Low. This code relates to the fuel and air metering system. The vehicle's computer detected a condition outside normal operating parameters and stored this code.

Symptoms of P004C

⚠️ Check Engine Light (MIL) illuminated
⚠️ Turbocharger/Supercharger Boost Control B reading at zero or minimum value
⚠️ Related system not functioning or in fail-safe mode
⚠️ Poor fuel economy

Common Causes

🔍 Open or broken wire in Turbocharger/Supercharger Boost Control B circuit
🔍 Poor ground connection at Turbocharger/Supercharger Boost Control B
🔍 Faulty Turbocharger/Supercharger Boost Control B with no output signal
🔍 Disconnected or loose Turbocharger/Supercharger Boost Control B connector
🔍 Blown fuse in related circuit

Frequently Asked Questions

What does P004C mean?

P004C indicates: Turbocharger/Supercharger Boost Control B Circuit Low. The vehicle's computer has detected that the Turbocharger/Supercharger Boost Control B is not operating within its expected parameters and stored this diagnostic trouble code.

Can I drive with code P004C?

You can drive short distances for essential trips, but schedule a diagnosis soon. Driving with P004C for extended periods may cause additional problems.

How much does it cost to fix P004C?

Repair costs for P004C typically range from $20 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

🔧 Repair broken wire or restore ground in Turbocharger/Supercharger Boost Control B circuit
🔧 Clean and secure Turbocharger/Supercharger Boost Control B connector and ground points
🔧 Replace failed Turbocharger/Supercharger Boost Control B

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.

P004C: Turbocharger/Supercharger Boost Control B Circuit Low