Circuit Description

WARNING: This page is about a different variant/trim than selected.

A flat type knock sensor (non-resonant type) has a structure that can detect vibrations over a wide band of frequencies: between approximately 6 kHz and 15 kHz.

Knock sensors are fitted onto the engine block to detect engine knocking.

The knock sensor contains a piezoelectric element which generates a voltage when it becomes deformed. The voltage is generated when the engine block vibrates due to knocking. Any occurrence of engine knocking can be suppressed by delaying the ignition timing.

Fig 1: DTC Detection Condition Trouble Area Chart

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HINT: When any of DTCs P0325, P0327 and P0328 are set, the ECM enters fail-safe mode. During fail-safe mode, the ignition timing is delayed to its maximum retardation. Fail-safe mode continues until the ignition switch is turned to OFF.

Reference: Inspection using an oscilloscope.

The correct waveform is shown.

KNK1 SIGNAL WAVEFORM REFERENCE

Item	Contents
Terminal	KNK1-EKNK
Equipment Setting	0.01 to 10V/Division, 0.01 to 10 msec./Division
Condition	keep the engine speed at 4,000 rpm with warm engine

Fig 2: KNK1 Signal Waveform