Toyota P0325 User's Manual
Contents
1. resistance between terminal KNK of the ECM connec tor and body ground OK Resistance 1 MQ or higher BE6653 A09086 Go to step 3 g Check knock sensor 1 See page SF 68 DOC Check for open and short in harness and connector between ECM and knock sensor 1 See page IN 30 D Repair or replace harness or connector 2000 CELICA RM744U DI 73 DIAGNOSTICS ENGINE EF Does malfunction disappear when a good knock sensor 1 is installed ves Replace knock sensor 1 Check and replace ECM See page IN 30 Reference INSPECTION USING OSCILLOSCOPE KNK signal waveform e With the engine racing 4 000 rpm measure between ter minal KNK of the ECM connector and body ground HINT The correct waveforms are as shown 0 5V Division m e Spread the time on the horizontal axis and confirm that 5 m sec Division period of the wave is 80 u sec Normal mode vibration frequency of knock sensor 0 5V a 12 5 kHz 1ZZ FE 7 1 kHz 2ZZ GE Division i HINT If normal mode vibration frequency is not 7 6 kHz the sensor is malfunctioning ilsec Division FI6510 FI6675 2000 CELICA RM744U2. DI 71 o DIAGNOSTICS ENGINE O OO 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 DTC Detecting Condition Trouble Area e Open or short in knock sensor 1 circuit No knock sensor 1 signal to ECM with engine speed 2 000 p P0325 e Knock sensor 1 looseness rpm or more ECM 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 Shielded K1 Knock Sensor 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 DI 72 DIAGNOSTICS ENGINE a Check continuity between terminal KNK of ECM connector and body ground PREPARATION a Remove the ECM cover b Disconnect the E5 connector of the ECM CHECK Measure
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