Knock Sensor: Removal

Disconnect the ground cable from battery.

Fig 1: Disconnecting Ground Cable From Battery
Courtesy of SUBARU OF AMERICA, INC.
Remove the air intake boot. < Ref. to REMOVAL , Air Intake Boot. >
Disconnect the connector (A) from the knock sensor, and remove the knock sensor from the cylinder block.

Fig 2: Locating Knock Sensor Mounting Bolt
Courtesy of SUBARU OF AMERICA, INC.