The knock sensor mounted on the cylinder block responds to high-frequency oscillations of the cylinder block and converts them into electrical signals, the magnitude of which increases with increasing detonation. Based on these signals, the ECM retards the ignition timing to eliminate detonation.
Examination
1. Disconnect the connector from the knock sensor and measure the resistance between terminals 1 and 2 of the connector. Resistance: more than 5 mΩ at 20°C.
2. If the resistance is out of specification, replace the sensor. Tightening torque: 16–25 Nm.
3. Measure the capacitance between terminals 1 and 2 of the connector. Capacitance: 800-1600 pf.