Toyota Tacoma manuals

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
1. Cooling fan relay Inspect the cooling fan relay continuity.  Using an ohmmeter, check that there is continuity between terminals 1 and 2. If there is no continuity, replace the relay.  Check that there is no continuity between terminals 3 and 5. If there is conti ...

Circuit description
The p squib (2nd step) circuit consists of the airbag sensor assy center and instrument panel passenger airbag assy. It causes the srs to deploy when the srs deployment conditions are satisfied. Dtc b1185/57 is recorded when a short is detected in the p squib (2nd step) circuit. Wiri ...

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 useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the ...

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