P0325

DTC P0325 Knock Sensor Circuit Malfunction

Component Location:

DESCRIPTION




Knocking is a phenomenon characterized by undesirable vibration and noise and can cause engine damage. The knock sensor (KS) is attached to the cylinder block and senses engine knocking. A knocking vibration from the cylinder block is applied as pressure to the piezoelectric element. The knock sensor (KS) detects vibration upon increase and decrease in engine RPM and generates a voltage based on this vibration. The ECM controls the ignition timing based on the amplitude and frequency of the knock sensor signal. For example, if engine knocking occurs, the ignition timing is retarded to suppress it. This DTC is set when the frequency goes outside a calibrated level.

Detecting Condition & Limp Home:

DTC DETECTING CONDITION

1. DTC Description
The ECM monitors the range of the analog input signal from knock sensor to check sensor failure that is short circuit or open circuit.
If the difference between knock signal and noise level is smaller than the threshold during defined time period, the DTC P0325 is set. In case the noise level is higher than the upper threshold or lower than the lower threshold, the DTC P0325 is set too. If same error code is set in the next driving cycle, the ECM illuminates the MIL.

2. Conditions for Setting the DTC

Schematic Diagram:

Signal Wave Form:

Step 1 - 3:

Step 4 - 6:

Inspection Procedure