P2256 moderate

Secondary Air Injection System Valve Stuck Closed (Bank 2)

The P2256 code means the vehicle's onboard diagnostic system has detected: Secondary Air Injection System Valve Stuck Closed (Bank 2). This is a moderate severity code.

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Keep driving?: Short distances only
DIY difficulty: moderate
Estimated cost: $150 - $600 (parts and labor)

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Common Symptoms

Check Engine Light on
Failed emissions test
Longer cranking time before start
Slight rough idle on cold start
Sulfur smell from exhaust on startup

Probable Causes (Ranked by Likelihood)

Secondary air valve stuck closed from carbon buildup Very High
Failed secondary air valve actuator High
Vacuum hose disconnected or cracked to air valve Moderate
ECM secondary air control circuit fault Low

Step-by-Step Diagnostic Procedure

Inspect secondary air valve for carbon buildup
Check vacuum supply to the air valve
Test air valve actuator operation
Verify ECM command to the air valve with scan tool

Frequently Asked Questions

What is the secondary air injection system?

The secondary air injection system pumps fresh air into the exhaust during cold start to help the catalytic converter reach operating temperature faster and reduce cold-start emissions.

Will this code cause my car to fail emissions?

Yes, secondary air injection codes will almost always cause an emissions test failure because the system is specifically designed to reduce startup emissions.

Can I delete the secondary air injection system?

Removing or disabling the secondary air system is illegal in most jurisdictions as it is a required emissions control component. The system should be repaired to maintain compliance.