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Toyota Corolla Repair Manual: Circuit description

A flat type knock sensor (nonresonant type) has the structure that can detect the vibration in a wider band of frequency from about 6 khz to 15 khz and has the following features.

Knock sensors are fitted on the cylinder block to detect the engine knocking.

The 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, the ignition timing is retarded to suppress it.

Hint:

Hint

: if the ecm detects the dtc p0325, it enters the failsafe mode in which the corrective retarded angle value is set to the maximum value.

Reference: inspection using the oscilloscope.

Reference: inspection using the oscilloscope.

  1.  After warming up run the engine at 4,000 rpm, check the waveform between terminal knk1 and eknk of the ecm connector.

Monitor description

The knock sensor, located on the cylinder block, detects spark knock. When spark knock occurs, the sensor picksup vibrates in a specific frequency range. When the ecm detects the voltage in this frequency range, it retards the ignition timing to suppress the spark knock.

The ecm also senses background engine noise with the knock sensor and uses this noise to check for faults in the sensor. If the knock sensor signal level is too low for more than 10 seconds, and if the knock sensor output voltage is out of normal range, the ecm interprets this as a fault in the knock sensor and sets a dtc.

Monitor strategy

Typical enabling conditions

Typical enabling conditions

Typical malfunction thresholds

Typical malfunction thresholds

Wiring diagram

Wiring diagram

Inspection procedure

Knock sensor 1 circuit
Dtc p0325 knock sensor 1 circuit (bank 1 or single sensor) Dtc p0327 knock sensor 1 circuit low input (bank 1 or single sensor) Dtc p0328 knock sensor 1 circuit high input (bank 1 or single senso ...

Inspection procedure
Hint: read freeze frame data using the hand-held tester or the obd ii scan tool. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, it is usefu ...

Other materials:

Inspection and adjustment procedure
1 Tire valve 2 Tire pressure gauge 1 Remove the tire valve cap. 2 Press the tip of the tire pressure gauge onto the tire valve. 3 Read the pressure using the gauge gradations. 4 If the tire inflation pressure is not at the recommended level, adjust the pressure. If you add too much air, pres ...

Inspection procedure
1 Check p squib circuit(airbag sensor assy center instrument panel passenger airbag assy) Disconnect the negative () terminal cable from the battery, and wait at least for 90 seconds.  disconnect the connectors between the airbag sensor assy center and the instrument panel pas ...

Switching the display
Press to display or hide the album title. If there is additional text, is displayed. Press and hold to display the remaining text. ■USB memory functions ●Depending on the USB memory that is connected to the system, the device itself may not be operable and certain function ...

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