Knock Sensor

NOTE: Knock sensor may also be referred to as knock sensor No. 1.

Knock sensor is located on side of cylinder block. See Fig 1-Fig 5 . Manufacturer recommends removing knock sensor from cylinder block before testing. See ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
Using ohmmeter, check that no continuity exists between electrical terminal on knock sensor and body of knock sensor. Replace knock sensor if continuity exists.

Fig 1: Locating Knock Sensor (Camry & Camry Solara)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 2: Locating Knock Sensor (Celica)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 3: Locating Knock Sensor (Corolla)

Fig 4: Locating Knock Sensor (RAV4)

Fig 5: Locating Knock Sensor (Tacoma & 4Runner)