Knock Sensor: Removal

Remove the collector cover.
Disconnect the ground cable from battery.

Fig 1: Disconnecting Ground Cable From Battery
Courtesy of SUBARU OF AMERICA, INC.
Remove the intake manifold. < Ref. to , REMOVAL , Intake Manifold. >
Disconnect the knock sensor connector.
Remove the knock sensor from cylinder block.

Fig 2: Removing Knock Sensor From Cylinder Block
Courtesy of SUBARU OF AMERICA, INC.