Celica Liftback L4-107.5 1762cc 1.8L DOHC (7A-FE) (1995)
Knock Sensor: Oscilloscope Patterns and Waveforms
With the engine racing (4,000 rpm) measure waveform between terminal KNK of engine control module and body ground. The correct waveform is as shown.
Spread the time on the horizontal axis, and confirm that the period of the wave is 123 microseconds (Normal mode vibration frequency of knock sensor: 8.1 KHz).
HINT: If normal mode vibration frequency is not 8.1 KHz, the sensor is malfunctioning.