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EFI Main Relay <--> [Main Relay (Computer/Fuel System)] > < Component Tests and General Diagnostics|Page 2249

Celica Liftback L4-107.5 1762cc 1.8L DOHC (7A-FE) (1995)

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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.

EFI Main Relay <--> [Main Relay (Computer/Fuel System)] > < Component Tests and General Diagnostics|Page 2249