Knock Sensor: Description and Operation
Knock Sensor (KS):
Knock Sensor Circuit Diagram:
PURPOSE
Varying octane levels in today's gasoline can cause detonation in high performance engines. Detonation is sometimes called spark knock.
To control spark knock a Knock Sensor (KS) system is used. This system is designed to retard spark timing up to 10° to reduce spark knock in the engine. This allows the engine to use maximum spark advance to improve driveability and fuel economy
OPERATION
The KS system has two major components:
^ KS module (located in the Powertrain control Module (PCM).
^ Check KS.
The KS detects abnormal vibration (spark knocking) in the engine. The sensor is mounted in the engine block near the cylinders. The sensor produces an A/C output voltage which increases with the severity of the knock. This signal voltage inputs to the PCM. The PCM then adjusts the Ignition Control (IC) timing to reduce spark knocking.