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Home >> Hyundai >> 2009 >> Elantra GLS, Automatic >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine Control/Fuel System (G4GC-GSL 2.0) >> Gasoline Engine Control System >> Knock Sensor (KS) >> Inspection >> Function And Operation Principle
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Function And Operation Principle

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

Fig 1: Identifying Knock Sensor (KS) Location
G05363727Courtesy of HYUNDAI MOTOR CO.
Fig 2: Identifying Knock Sensor (KS) Components
G04884269Courtesy of HYUNDAI MOTOR CO.