Circuit description

The 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.


DTC Detecting Condition

Trouble Area


No knock sensor 1 signal to ECM with engine speed, 2,000 rpm or more

• Open or short in knock sensor 1 circuit

• Knock sensor 1 (looseness)

If the ECM detects above diagnosis conditions, it operates the fail safe function in which the corrective retard angle value is set to the maximum value.

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