WARNING: This page is about a different car, the 2007 Pontiac G5 Pursuit, 2007 Pontiac G5, and 2007 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: View Of Knock Sensor (KS) Electrical Connector
Courtesy of GENERAL MOTORS CORP.
Disconnect the knock sensor (KS) electrical connector (3).