WHERE IS THE KNOCK SENSOR ON A 2006 CHEVY COBALT TO REPLACE IT.
Not related to the O2 sensor. Located on the front of the engine just
above the starter KNOCK SENSOR (KS) SYSTEM DESCRIPTION
The knock sensor (KS) system enables the engine control module (ECM) to
control the ignition timing for the best possible performance while
protecting the engine from potentially damaging levels of detonation.
The ECM uses the KS system to test for abnormal engine noise that may
indicate detonation, also known as spark knock.
The knock sensor (KS) system uses a flat response 2-wire sensor. The
sensor uses piezo-electric crystal technology that produces an AC
voltage signal of varying amplitude and frequency based on the engine
vibration, or noise, level. The amplitude and frequency are dependant
upon the level of knock that the KS detects. The engine control module
(ECM) receives the KS signal through a signal circuit. The KS ground is
supplied by the ECM through a low reference circuit.
The ECM learns a minimum noise level, or background noise,
at idle from the KS and uses calibrated values for the rest of the RPM
range. The ECM uses the minimum noise level to calculate a noise
channel. A normal KS signal will ride within the noise channel. As
engine speed and load change, the noise channel upper and lower
parameters will change to accommodate the KS signal, keeping the signal
within the channel. In order to determine which cylinders are knocking,
the ECM only uses KS signal information when each cylinder is near top dead center (TDC) of the firing stroke. If knock is present, the signal will range outside of the noise channel.
If the ECM has determined that knock is present, it will ****** the
ignition timing to attempt to eliminate the knock. The ECM will always
try to work back to a zero compensation level, or no spark ******. An
abnormal KS signal will stay outside of the noise channel or will not be
present. KS diagnostics are calibrated to detect faults with the KS
circuitry inside the ECM, the KS wiring, the KS voltage output, or
constant noise from an outside influence such as a loose/damaged
component or excessive engine mechanical noise.
Feb 24, 2011 |
2006 Chevrolet Cobalt