Knock Sensor: Testing and Inspection

KNOCK SENSOR
The knock sensor is attached to the cylinder block and senses engine knocking conditions. A knocking vibration from the cylinder block is applied as pressure to the piezoelectric element. This vibrational pressure is then converted into a voltage signal which is delivered as output. If engine knocking occurs, ignition timing is retarded to suppress it.




CIRCUIT DIAGRAM




TROUBLESHOOTING PROCEDURES

TROUBLESHOOTING HINTS
1. The MIL is ON or the DTC is displayed on the HI-SCAN under the following condition;
- When the knock sensor signal is not detected though the engine is in the over load condition.

2. When knock sensor signal is abnormally low.

Harness Inspection Procedure:

HARNESS INSPECTION PROCEDURE




SENSOR INSPECTION
1. Disconnect the knock sensor connector.
2. Measure resistance between the terminal 1 and 2.

Standard value about 5 Mohms [at 20 °C (68 °F)]

3. If the resistance is continual, replace the knock sensor.

Knock sensor 16 - 28 Nm (160 - 250 kg.cm, 11.8 - 18.4 lb.ft)

4. Measure the capacitance between the terminal 1 & 2.

Standard value 800-1600 pF