LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Kia >> 2009 >> Optima EX, 2.4 8 >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine Control System - 2.4L >> Knock Sensor (KS) >> Description And Operation >> Function And Operation Principle
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Function And Operation Principle

Knocking is a phenomenon characterized by undesirable engine detonation or pinging that can cause engine damage. Knock Sensor (KS) senses engine and cylinder block knocking. When knocking occurs, the vibration from the cylinder block is applied as pressure to the piezoelectric element. The sensor transfers the voltage signal higher than the specified value to the PCM and the PCM retards the ignition timing. If the knocking disappears after retarding the ignition timing, the PCM will advance the ignition timing. This sequential control can improve engine power, torque and fuel economy.

Fig 1: Identifying Knock Sensor
G06361946Courtesy of KIA MOTORS AMERICA, INC.
Fig 2: Identifying Spring Washer, Load Washer, Insulator And Sleeve
G06361947Courtesy of KIA MOTORS AMERICA, INC.