Knock Sensor: Testing and Inspection

KNOCK SENSOR (KS)




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

Circuit Diagram:

CIRCUIT DIAGRAM

Troubleshooting Procedures:

TROUBLESHOOTING PROCEDURES

TROUBLESHOOTING HINTS

1. The MIL is ON or the DTC is displayed on the HI-SCAN PRO under the following condition:
- When the knock sensor signal is not detected even though the engine is in an overload condition.
- When the knock sensor signal is abnormally low.

HARNESS INSPECTION PROCEDURES

Refer to "P0325" DTC inspection procedures.

SENSOR INSPECTION

1. Disconnect the knock sensor connector.
2. Measure the resistance between terminals 2 and 3

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

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

Knock sensor:
16-25 Nm (160-250 kg.cm, 11.8-18.4 lb.ft)




4. Measure the capacitance between the terminal 2 and 3

Standard value: 800-1600 pF