Grand AM L4-144 2.4L DOHC VIN T SFI (1997)
Knock Sensor: Description and Operation
Knock Sensor
Description
The Knock Sensor (KS) detects abnormal vibration (spark knocking) in the engine. The sensor is mounted in the engine block near the cylinders.
The sensor produces an AC output voltage which increases with the severity of the knock. This signal voltage is sent to the Powertrain Control
Module (PCM). The PCM then adjusts the Ignition Control (IC) timing to reduce the spark knock.
The Knock Sensor system is designed to retard the spark timing up to 15 degrees in order to reduce a spark knock in the engine. This allows the
engine to use a maximum spark advance in order to improve driveability and fuel economy.
Operation
The knock sensor is mounted into the engine block near the cylinders. The knock sensor produces an AC voltage which increases with the severity
of the knock. This signal voltage inputs to the PCM. The PCM then adjusts the IC timing to reduce spark knocking.
Circuit Faults
A fault in the KS circuit or module will set a DTC P0325.
