Troubleshooting

DTC P0325 Knock Sensor 1 Circuit Malfunction

CIRCUIT DESCRIPTION
knock sensors are fitted one to the right bank and left bank of the cylinder block to detect engine knocking. This 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, ignition timing is retarded to suppress it.
If the ECM detects the above diagnosis conditions, it operates the fail-safe function in which the corrective retard angle value is set to the maximum value.





DETECTING CONDITION

HINT: DTC P0325 is for right bank knock sensor circuit. DTC P0300 is for the left bank knock sensor circuit.





WIRING DIAGRAM

Reference INSPECTION USING OSCILLOSCOPE





- With the engine racing (4,000 rpm) measure between terminals KNKR, KNKL of ECM and body ground.

HINT: The correct waveform is as shown.





- Spread the time on the horizontal axis, and confirm that period of the wave is 141 micro sec.
(Normal mode vibration frequency of knock sensor: 7.1 kHz)

HINT: If normal mode vibration frequency is not 7.1 kHz, the sensor is malfunctioning.

Step 1:

Step 2:

Step 3:

INSPECTION PROCEDURE