P0325

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

CIRCUIT DESCRIPTION

DTC Detecting Condition:

Knock sensor is fitted on the cylinder block to detect the 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: If the ECM detects the DTC "P0325", it enters the fail-safe mode in which the corrective retarded angle value is set to the maximum value.







Reference: Inspection using the oscilloscope.

HINT: The correct waveform is as shown.

MONITOR DESCRIPTION

Monitor Strategy:

Typical Enabling Conditions:

Typical Malfunction Thresholds:

The knock sensor, detects spark knock. When spark knock occurs, the sensor picks-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 out of normal range, the ECM interprets this as a fault in the knock sensor and sets a DTC.

Wiring Diagram:

Step 1 - 3:

Step 4:

INSPECTION PROCEDURE

HINT: Read freeze frame data using the hand-held tester or the OBD II scan tool. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio was lean or rich, etc. at the time of the malfunction.