Troubleshooting

DTC P0325 - Knock Sensor Circuit Malfunction
(Knock Sensor 1, Right bank)

CIRCUIT DESCRIPTION
Knock sensors are fitted one each 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.

DETECTING CONDITION



NOTE: 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.

WIRING DIAGRAM





INSPECTION PROCEDURE

HINT:
DTC P0325 is for right bank knock sensor circuit.
DTC P0330 is for left bank knock sensor circuit.














Reference INSPECTION USING OSCILLOSCOPE



- With the engine racing (4,000 rpm) measure between terminals KNKR, KNKL of ECM and body ground.
- The correct waveform appears as shown in the illustration on the left.




- 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).
- If normal mode vibration frequency is not 7.1 KHz, the sensor is malfunctioning.