P0415 Secondary Air Injection System Switching Valve B Circuit Malfunction

P0415 indicates a malfunction in Secondary Air Injection System Switching Valve B circuit. The valve B control path is not behaving as expected electrically.

Code details

Generic OBD-II · P0

System: Emissions
Code type: Generic (SAE / ISO controlled)
Standard: SAE J2012 / ISO 15031-6

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not assume valve B is mechanically stuck until the circuit power, ground, control, and solenoid have been tested.

Symptoms of P0415

Check-engine light, often with no obvious change in how the car drives.
A failed emissions test or incomplete readiness monitors.
Sometimes a faint fuel-vapour smell (on EVAP codes).

Common causes of P0415

A worn catalytic converter or an oxygen/air-fuel sensor reading out of range.
EVAP leaks — a loose or failed gas cap, cracked hose, or purge/vent valve.
Exhaust leaks, fuel-trim problems, or a fault in a related monitor.

Useful checks before replacing parts

Check valve B command, control voltage, fuse and relay status, ground path, freeze-frame temperature, and secondary air monitor state.
Inspect valve B wiring, connector condition, solenoid resistance, vacuum routing if equipped, check valve operation, and water intrusion.
Command valve B with a scan tool and confirm the electrical command produces the expected airflow change.

Related OBD-II codes

These nearby emissions entries can help compare wording and pin down the fault area.