P0325

DTC P0325 KNOCK SENSOR 1 CIRCUIT (BANK 1 OR SINGLE SENSOR)

CIRCUIT DESCRIPTION

DTC Detection Conditions:

The knock sensor is fitted on 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, the ignition timing is delayed to suppress it.






HINT: When DTC P0325 is set, the ECM enters fail-safe mode. During fail-safe mode, the ignition timing is retarded to its maximum retardation. Fail-safe mode continues until the ignition switch is turned to OFF.




Reference: Inspection using an oscilloscope.

HINT: The correct waveform is shown on the left.

MONITOR DESCRIPTION

Monitor Strategy:

Typical Enabling Conditions:

Typical Malfunction Thresholds:

The knock sensor detects spark knock. When spark knock occurs, the sensor pick-up vibrates in a specific frequency range. When the ECM detects 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 seconds, and if the knock sensor output voltage is outside the normal range, the ECM interprets this as a malfunction in the sensor and sets the DTC.

Wiring Diagram:

Step 1 - 3:

Step 4:

INSPECTION PROCEDURE

HINT: Read freeze frame data using a hand-held tester or OBD II scan tool. Freeze frame data record the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data, from the time the malfunction occurred.