P2440 Subaru Secondary Air Injection System Switching Valve Stuck Open

Possible causes

– Faulty Vacuum Switching Valve (VSV)
– Vacuum Switching Valve (VSV) harness is open or shorted
– Vacuum Switching Valve (VSV) circuit poor electrical connection
– Faulty Pressure Sensor
– Faulty Air Switching Valve

What about the obd code?

If the Engine Control Module (ECM) receives the pulsation signal from the sensor despite the ECM ordering the VSV to close the air switching valve, or if the ECM has not received the signal from the sensor despite the ECM ordering the VSV to open the valve, the ECM interprets this as a fault in the secondary air injection system and the code is set.

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)

P2440 Subaru Description

To accelerate the activation of catalyst when warming up the engine, the air injection system pumps the secondary air to the exhaust manifold by pressure. The secondary air is supplied by the air pump and it is pumped to the exhaust manifold through the air switching valve. Open and close movement of the air switching valve is regulated by the Vacuum Switching Valve (VSV).The air pump and the air switching valve are observed by the Engine Control Module (ECM) and are used to detect malfunction in this system. The ECM monitors the secondary air injection system and detects malfunction using a pressure sensor located on the air switching valve.

The ECM observes the pressure in the secondary air passage using the pressure sensor located on the air switching valve in the secondary air injection system. The sensor detects an exhaust pressure in the secondary air passage.