Hyundai Sonata LF: Engine Control System / Knock Sensor (KS) Description and Operation
Knocking is a phenomenon characterized by undesirable
vibration and noise and can cause engine damage. Knock Sensor (KS) is
installed on the cylinder block and senses engine knocking.
When knocking occurs, the vibration from the cylinder block
is applied as pressure to the piezoelectric element. When a knock
occurs, the sensor produces voltage signal. The ECM retards the ignition
timing when knocking occurs. 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.

Inspection
1.
Check the signal waveform of the CMPS and CKPS using the GDS.
Specification: Refer to “Wave Form”
Removal
•
DON’T remove the camshaft position sensor while the engine
is running or right after engine is turned off...
Other information:
C..
Description
Ambient Temperature Sensor (ATS) is installed on the
front-end module and senses the ambient temperature. ECM receives not
only the intake air temperatue but also the ambient air temperature
informations at the same time to control the intake air quantity
precisely provided through the turbo charger...