Subaru Oxygen Sensor 22641-AA420 / AA420A Electronic Fuel Injection Parts

When your Subaru shows idle instability, obvious fuel consumption increase, weak acceleration, or engine fault light, it is likely due to aging oxygen sensor failing to monitor exhaust oxygen content accurately. Properly functioning, it feeds a continuous signal to the ECU to help control injection and ensure combustion efficiency and emissions compliance. Fits many Subaru models; OEM numbers 22641-AA420 / AA420A. Use a dedicated socket during installation to avoid damaging threads; clean exhaust pipe end before installation and apply a small amount of anti-seize to prevent high-temperature seizing.