Secondary Air Injection System Switching Valve Stuck Closed (Bank 1)
The switching valve on bank 1 will not open when commanded, so no secondary air reaches the exhaust during cold start. Catalyst light-off is delayed and emissions during the cold-start window rise.
Affected components
- Secondary air switching valve
- Secondary air vacuum lines
Common causes
- High likelihood: Switching valve stuck closed by carbon
- Medium likelihood: Vacuum control line leak
- Low likelihood: Carbon or debris buildup preventing free movement
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
- A drive cycle may be required after repair
Related codes
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.