Celica GT Ltd Ed Convertible L4-2164cc 2.2L DOHC MFI (1997)
Knock Sensor: Description and Operation
CIRCUIT DESCRIPTION
A knock sensor is fitted to the cylinder block to detect engine knocking. This sensor contains a piezoelectric element which generates a voltage
when it becomes deformed, which occurs when the cylinder block vibrates due to knocking. If engine knocking occurs, ignition timing is retarded
to suppress it.
If the ECM detects the above diagnosis conditions, it operates the fail safe function in which the corrective retard angle value is set to the
maximum value.
