DI–71
DIAGNOSTICS
–
ENGINE
DI38A–03
DTC
P0325 Knock Sensor 1 Circuit Malfunction
CIRCUIT DESCRIPTION
The knock sensor is fitted to the cylinder block to detect engine knocking. This sensor contains a piezoelec-
tric element which generates a voltage when it becomes deformed, which occurs when the cylinder block
vibrates due to knocking. If engine knocking occurs, ignition timing is retarded to suppress it.
DTC No.
DTCDetectingCondition
TroubleArea
S Open or short in knock sensor 1 circuit
S Knock sensor 1 (looseness)
S ECM
No knock sensor 1 signal to ECM with engine speed, 2,000
rpm or more
P0325
HINT:
If the ECM detects above diagnosis conditions, it operates the fail safe function in which the corrective retard
angle value is set to the maximum value.
WIRING DIAGRAM
ECM
27
E5
1
EB1
W
KNK1
W
A
(Shielded)
J1
J/C
1
A
BR
K1
Knock Sensor
ED
A09120
INSPECTION PROCEDURE
HINT:
Read freeze frame data using TOYOTA hand–held tester or OBD II scan tool. Because freeze frame records
the engine conditions when the malfunction is detected, when troubleshooting it is useful for determining
whether the vehicle was running or stopped, the engine warmed up or not, the air–fuel ratio lean or rich, etc.
at the time of the malfunction.
2000 CELICA (RM744U)
