Subaru 22641AA36A Air Fuel Ratio Sensor Assembly

The sensor's electrical harness should be traced to its connector, which is typically found in the rear of the engine compartment. The connector should be disconnected, and the sensor should be unscrewed and removed. The threads of the sensor bore in the exhaust manifold should be cleaned, and if the old sensor is being installed, anti-seize compound should be applied to the threads.

To service the oxygen sensor in turbocharged models, start by disconnecting the cable from the negative terminal of the battery. Then, disconnect the upstream oxygen sensor electrical connector and detach the clips for the upstream oxygen sensor harness. Loosen the right front wheel lug nuts and raise the front of the vehicle, supporting it securely on jackstands. Remove the right front wheel and the fasteners from the service hole cover near the front of the inner fender splash shield. Remove the cover and unscrew the oxygen sensor. Apply anti-seize compound to the threads of the sensor to facilitate future removal if installing the old sensor. Installation is otherwise the reverse of removal.