Toyota Corolla (E120) 2002–2008 Repair Manual / Diagnostics / Sfi system / Knock sensor 1 circuit / Circuit description
Toyota Corolla (E120): 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
: 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.
- 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 malfunction thresholds
Wiring diagram
Other materials:
Power outlet
Please use as a power supply for electronic goods that use less than 12 VDC/10
A (power consumption of 120 W).
Open the lid.
■The power outlet can be used when
► Vehicles without a smart key system
The engine switch is in the “ACC” or “ON” position.
► Vehicles with ...
Lubrication system
*: The engine oil capacity is a reference quantity to be used when changing the
engine oil. Warm up and turn off the engine, wait more than 5 minutes, and check
the oil level on the dipstick.
■ Engine oil selection
“Toyota Genuine Motor Oil” is used in your Toyota vehicle. Use Toyo ...
If the vehicle is submerged or
water on the road is rising
This vehicle is not designed
to be able to drive on roads
that are deeply flooded with
water. Do not drive on roads
where the roads may be
submerged or the water
may be rising. It is dangerous
to remain in the vehicle,
if it is anticipated that the
vehicle will be flooded or
set adrift. Remain calm ...