Toyota Celica 2005 Repair Manual page 374

MONITOR DESCRIPTION
The knock sensor located on the cylinder block, detects spark knock.
When spark knock occurs, the sensor pick−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 sec., 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
Related DTCs
Required sensors/components
Frequency of operation
Duration
MIL operation
Sequence of operation
TYPICAL ENABLING CONDITIONS
Item
The monitor will run whenever this DTC is
not present
Battery voltage
Idle
Time after engine start
Engine coolant temperature
Intake air amount per revolution
TYPICAL MALFUNCTION THRESHOLDS
Detection Criteria
Sensor failure is indicated when the knock sensor output
level is below the specific threshold for:
2005 CELICA (RM1131U)
DIAGNOSTICS −
P0325
Main sensors/components
Related sensors/components
Continuous
10 sec.
Immediate
None
Minimum
10 V
5 sec.
60_C (140_F)
0.3 g/rev
373
ENGINE (1ZZ−FE)
Knock sensor (Bank 1) range check or rationality
Knock sensor
Crankshaft position sensor, Camshaft position
sensor, Engine coolant temperature sensor,
Mass air flow meter
Specification
See page DI−3
OFF
Threshold
10 sec.
DI−175
Maximum
−
−
−
−