Knock Sensor: Removal

Remove the collector cover.
NOTE: Follow these procedures for removal of the collector cover.
1. Lift up the rear side holding two positions (A).
2. Lift up the front side holding two positions (B) while moving it in the forward direction of the vehicle.
  
  Fig 1: Removing Collector Cover
  Courtesy of SUBARU OF AMERICA, INC.
Disconnect the ground cable from battery.
Remove the intake manifold. Refer to REMOVAL .
Disconnect the knock sensor connector.
Remove the knock sensor from cylinder block.

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