Toyota Tacoma manuals

Toyota Corolla Repair Manual: Circuit description

A flat type knock sensor (non–resonant 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 fail–safe 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 picks–up 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:

Basic inspection
Resistance measuring condition of electronic parts  unless stated, all resistance is measured at an ambient temperature of 20 c (68 °F). As the resistance may be outside the specifications if measured at high temperatures immediately after the vehicle has been running, measur ...

Inspection procedure
Hint: start the inspection from step 1 in case of using the hand–held tester and start from step 2 in case of not using the hand–held tester. 1 Read value of hand–held tester(front speed sensor) Select the datalist mode on the hand–held tester.  check that there is no difference betw ...

Replacement
Hint: for parking brake cable assy no.2, Perform the same procedure to the parking brake cable assy no.3. 1. Remove rear wheel 2. Remove rear brake drum sub–assy 3. Remove rear brake automatic adjust lever lh 4. Remove front brake shoe  sst 09718–00010 5. Remove parking brake shoe st ...

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