Knock Sensor

Use an ohmmeter which can measure more than 10 MΩ.

Disconnect knock sensor harness connector.
Check resistance between terminal 1 and ground.
Resistance :500 - 620 kΩ [at 25°C (77°F)]

CAUTION: Discard any knock sensors that have been dropped or physically damaged. Use only new ones.

Fig 1: Checking Resistance Between Terminal And Ground

Courtesy of NISSAN MOTOR CO., U.S.A.