Knocking is a phenomenon characterized by undesirable vibration and noise that can cause engine damage. A knock sensor (KS) is mounted on the cylinder block and senses engine knocking. A knocking vibration from the cylinder block is applied as pressure to the piezoelectric element. A knock sensor (KS) detects vibration when RPM rises or drops and generates voltages based on this vibration. The PCM 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 prevent it.
Checking the range of input signal with a knock sensor under detecting condition, PCM senses open in knock sensor circuit or malfunction of sensor. If a knock signal or noise level is inputted without the specified value during standard duration, PCM sets P0325. MIL(Malfunction Indication Lamp) turns on when the malfunction lasts till consecutive 2 driving cycle.
Item
Detecting Condition
Possible cause
DTC Strategy
? Signal open
? Poor connection
? Open in harness
? Knock sensor
? PCM
Enable Conditions
? Pressure in intake manifold is normal.
? Engine speed = 2000 rpm
Threshold value
? Filter coefficient < 1.0
Diagnosis Time
? Continuous
MIL On Condition
? No MIL ON(DTC only)