Knock Sensor: Testing and Inspection

Inspection
1. Disconnect knock sensor connector and remove knock sensor from vehicle. Mount knock sensor in the jaws of a bench vise and connect a voltmeter between terminals 1 and 2.
2. Wrap on the bench vise sharply with a hammer and observe voltmeter.
3. Verify that a voltage spike (less than 1 V) is output from the knock sensor.
4. If no voltage spike is observed, replace the knock sensor.