P0325

DTC P0325









GENERAL DESCRIPTION
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.

DTC DESCRIPTION
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.

DTC Detecting Condition:

DTC DETECTING CONDITION

Schematic Diagram:

SCHEMATIC DIAGRAM




SIGNAL WAVEFORM AND DATA

MONITOR SCANTOOL DATA
1. IG "OFF"& connect Scantool.
2. ENG "ON" and warm -up the engine to normal operating temperature.




3. Monitor item related to knock sensor on the service data.
4. Is the service data displayed correctly?

YES - Fault is intermittent caused by poor contact in the sensor`s and/or PCM`s connector or was repaired and PCM memory was not cleared. Thoroughly check connectors for looseness, poor connection, ending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure

NO - Go to "Terminal and connector inspection" procedure

TERMINAL AND CONNECTOR INSPECTION
1. Many malfunctions in the electrical system are caused by poor harness and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
2. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination,deterioration, or damage.
3. Has a problem been found?

YES - Repair as necessary and go to "Verification of Vehicle Repair" procedure

NO - Go to "Signal Circuit Inspection" procedure.

SIGNAL CIRCUIT INSPECTION
1. Check open in harness
a. IG "OFF" and disconnect knock sensor connector and PCM connector.
b. Measure resistance between terminal 1 of knock sensor harness connector and terminal 55 of PCM harness connector.




c. Measure resistance between terminal 2 of knock sensor harness connector and terminal 56 of PCM harness connector.

Specification : Below 1 ohm

d. Is the measured resistance within specification?

YES - If the problem is corrected after substituting with a known - good knock sensor, replace it. If the problem is pending, check for proper operating after substituting with a known - good PCM. and then if the problem is corrected, replace PCM and go to "Verification of Vehicle Repair" procedure.

NO - Repair open in harness, and go to "Verification of Vehicle Repair" procedure.

NOTE: There is a memory reset function on Scantool that can erase optional parts automatically detected and memorized by PCM. After testing PCM on the vehicle, use this function to reuse the PCM on the others

VERIFICATION OF VEHICLE REPAIR
After a repair, it is essential to verify that the fault has been corrected.
1. Monitor and record the Freeze Frame Data for the Diagnostic Trouble Code(DTC) which has been diagnosed.
2. Using a Scantool, Clear the DTCs
3. Operate the vehicle within conditions noted in the freeze frame data or enable conditions
4. Monitor that all readiness test have been verified as "Complete".
5. Are any DTCs present?

YES - Go to the applicable troubleshooting procedure.

NO - System is performing to specification at this time.