Motronic ME 7.1.1
Knock Sensor (KS) 1 G61 and Knock Sensor (KS) 2 G66
The knock sensors are threaded into the crankcase.
They detect combustion knocks in individual cylinders.
To prevent combustion knock, a cylinder selective
knock control overrides the electronic control of the
ignition timing.
360_157
360_158
KS2 G66
KS1 G61
Signal Utilization
Effects of Signal Failure
Based on the knock sensor signals, the ECM initiates
ignition timing adjustment in the knocking cylinder
until knocking stops.
If a knock sensor fails, the ignition timing for the
affected cylinder group is retarded. This means that a
safety timing angle is set in the “late“ direction. This
can lead to an increase in fuel consumption. Knock
control for the cylinder group of the remaining knock
sensor remains in effect.
Knock sensors MUST be properly
torqued or they will send incorrect
signals to the ECM. A loose sensor
can indicate knocking where there is
none, and a tight sensor may not report
engine knocking.
If both knock sensors fail, the engine management
system goes into emergency knock control in which
the ignition angle is retarded across the board so that
full engine power is no longer available.
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