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:
If the vehicle becomes stuck
Carry out the following procedures
if the tires spin or
the vehicle becomes stuck
in mud, dirt or snow:
Recovering procedure
1. Stop the engine. Set the
parking brake and shift the
shift lever to P.
Do not press the shift release button
after shifting the shift lever to P.
2. Remove the mud, snow ...
Roof drip side finish moulding center lh
Replacement
Hint:
use the same procedures for the rh side and lh side.
The installation procedures are the removal procedures in reverse
order. However, only installation
procedures requiring additional information are included.
1. Remove roof drip side finish moulding center lh
...
Diagnosis system
Description
when troubleshooting obd ii vehicles, the only difference
from the usual troubleshooting procedure
is that you need to connect an obd ii scan tool complying
with sae j1987 or a hand–held tester to the
vehicle, and read off various data output from the
vehicle†...