Knock Sensor: Description and Operation

PURPOSE:
The Knock Sensor (KS) is used to detect engine detonation (ping). The ECM will retard the electronic spark timing up to 8~ based on the signal received.

LOCATION
Engine block below right bank of cylinders.

CONSTRUCTION
The KS system has two major components:
- KS Module.
- Knock Sensor

OPERATION
When the KS detects abnormal vibration (spark knocking) in the engine, it produces a voltage that is received by the KS module. As long as the KS module sees no voltage from the KS (knock not present), it sends a signal voltage (8 to 10 volts) to the ECM and the ECM provides normal spark advance. When the module detects voltage from the KS (knock present), it turns "OFF" the signal to the ECM and the voltage at terminal "B7" goes to 0 volt. The ECM then retards Ignition System timing to reduce spark knock.