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:
Operation and Leakage Check
Check all of the following items:
ComponentProcedureBrake Booster (A)Check brake operation by applying the brakes during a test
drive. If the brakes do not work properly, check the brake booster.
Replace the brake booster as an assembly if it does not work properly or
if there are signs of leakage...
S..