Knock Sensor

Deviation of the octane rating from specification in modern gasoline can cause engine knock, also called "spark knock". When there is no knock, the sensor sends a voltage signal to the control module, which sets the ignition timing to optimum. When the knock sensor detects abnormal pressure spikes (knock), the control module retards the ignition timing until the knock stops. If the sensor malfunctions in any way, code 52 is stored in memory.

Inspection

PROCEDURE

1. The knock sensor (indicated by the arrow) is installed on the inner side of the engine (on the engine compartment bulkhead side), under the intake manifold. To access the knock sensor, remove the intake manifold cover and the intake manifold (refer to subsection 3.1.1.4).
2. Connect an ohmmeter to the sensor terminal and to the body. The meter must show an open circuit.
3. If the circuit is closed, replace the knock sensor.