How much does it cost to fix P0400?

Typical repair cost is $100–$700.

P0400 — Exhaust Gas Recirculation Flow Malfunction

Medium Severity · Emissions

OBD-II code P0400 means your vehicle's ECU detected: Exhaust Gas Recirculation Flow Malfunction. Below: causes, step-by-step fixes, and repair cost — free, no signup needed.

Drivable short-term but schedule a diagnosis soon. Prolonged driving can worsen the issue.

Typical Repair Cost

$100–$700

Parts + labor, national average

Severity

Medium

Schedule repair soon

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Common Causes of P0400

Clogged EGR valve
Failed EGR solenoid
Blocked EGR passages

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How to Fix Code P0400

Clean EGR valve

Test EGR solenoid

Replace EGR valve ($150–$400)

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FAQ — Code P0400

What does OBD-II code P0400 mean?

P0400 means your vehicle's onboard computer detected: Exhaust Gas Recirculation Flow Malfunction. This is a medium-severity code in the Emissions category.

How much does it cost to fix code P0400?

Typical repair cost for P0400 is $100–$700 including parts and labor. Costs vary by vehicle make, model, and location. A free scan at AutoZone or O'Reilly is a good first step.

Can I drive my car with code P0400?

Code P0400 is generally safe for short trips, but have it diagnosed soon to prevent the problem from worsening.

What are the most common causes of P0400?

The most common causes are: Clogged EGR valve, Failed EGR solenoid, Blocked EGR passages. Always start with the cheapest diagnosis step before replacing parts.

Will code P0400 clear itself?

Code P0400 will clear itself after the underlying issue is fixed and the ECU completes several successful drive cycles. Clearing it without fixing the root cause only masks the problem temporarily.

Is P0400 showing on your car?

Enter your VIN for a free vehicle-specific report — recalls, specs, and market value. No signup required.

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Related Emissions Codes

P0401EGR Flow Insufficient P0402EGR Flow Excessive P0403EGR Control Circuit Malfunction P0404EGR Control Circuit Range/Performance P0410Secondary Air Injection System Malfunction P0420Catalyst System Efficiency Below Threshold...

OBD-II code data is based on SAE J2012 standards and general repair industry data. Repair costs are national averages and vary by vehicle, location, and shop. Always consult a qualified mechanic for a diagnosis specific to your vehicle.