Knock Sensor: Removal

Remove the collector cover.
1. Carefully pull up the rear of collector cover at two positions (A).
2. Carefully pull up the front of collector cover at two positions (B) while moving it forward.
  
  Fig 1: Removing Collector Cover
  Courtesy of SUBARU OF AMERICA, INC.
Disconnect the ground terminal from battery sensor. < Ref. to BATTERY , NOTE, Repair Contents. >
Remove the intake manifold. < Ref. to REMOVAL , Intake Manifold. >
Disconnect the connector (A) from the knock sensor, and remove the knock sensor from the cylinder block.

Fig 2: Identifying Knock Sensor Connector Bolts
Courtesy of SUBARU OF AMERICA, INC.