Knock Sensor: Testing and Inspection

INSPECTION

1. INSPECT KNOCK SENSOR




a. Measure the resistance of the sensor.

Standard resistance: 120 to 280 k at 20 degrees C (68 degrees F)

If the result is not as specified, replace the knock sensor.

DESCRIPTION

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.

DTC Detection Condition:

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.









HINT: When any of DTCs 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 OFF.

Reference: Inspection using an oscilloscope. The correct waveform is given.