TESTING

NOTE: The knock sensor test requires the use of an oscilloscope.

1. Position test probe of oscilloscope lead to the oscilloscope pick-up point as shown in the illustration.
2. Start the engine and allow to idle. Accelerate the engine to a maximum speed of 5,000 rpm and check the waveform on the scope.

   Fig. 1: Knock sensor circuit. Note positioning of oscilloscope during testing.

   Fig. 2: Ideal test pattern of knock sensor as seen on an oscilloscope

3. If the test pattern obtained differentiates from the desired pattern shown in the illustration, replace the knock sensor.