3.8 LITER W/GT3. Changeover valve. A switch which opens or closes based on a predetermined boost value. Controls fresh air inlet for secondary air injection system. Secondary Air Injection Pump Check Valve. Secondary Air Injection Solenoid. Change - over valve. Changeover valve. CONTROL SOLENOID. DIVERTER VALVE. Secondary Air Injection Control Valve. Secondary Air Injection Pump Check Valve. Secondary Air Injection Solenoid. Turbocharger Boost Pressure Safety Switch.