The operation of the Knock Sensor (KS) is to monitor pre-ignition or "engine knocks" and send the signal to the PCM. The PCM responds by adjusting ignition timing until the "knocks" stop. The sensor works by generating a signal produced by the frequency of the knock as recorded by the piezoelectric ceramic disc inside the KS. The disc absorbs the shock waves from the knocks and exerts a pressure on the metal diaphragm inside the KS. This compresses the crystals inside the disc and the disc generates a voltage signal proportional to the frequency of the knocks ranging from zero to 1 volt.
Removal & Installation
For access to the Knock Sensors, refer to Engine Mechanical Components-Intake Manifold-Removal and Installation.
- Remove the 2 Knock Sensor bolts, and remove the Knock Sensors.
- To install, tighten the Knock Sensor bolts to 18 ft. lbs. (25 Nm).
Knock Sensor Pin Testing
This pinpoint test is intended to diagnose the following: