3.
Monitor the "Knock sensor" parameters on the scantool.
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.
If the signal of knock sensor is less than threshold under enable conditions, PCM sets P0325.
Item | Detecting Condition | Possible Cause |
DTC Strategy | ● Sensor signal check | ● Poor connection ● Open or short in signal circuit ● Knock sensor ● PCM |
Enable Conditions | ● Engine coolant temperature 〉 40℃ ● Engine speed 〉 2600 rpm | |
Threshold Value | ● Sensor signal ＜ threshold(which is the function of engine speed.) | |
Diagnostic Time | ● Continuous | |
MIL | ● OFF |
Item | Specification |
Capacitance | 950 ~ 1,350pF |
Connect scantool to DLC(Data Link Cable).
Warm up the engine to normal operating temperature.
Monitor the "Knock sensor" parameters on the scantool.
Are the parameters displayed correctly ?
▶ Fault is intermittent caused by poor contact in the sensor’s and/or ECM’s connector or wasrepaired and ECM memory was not cleared. Thoroughly check connectors for looseness, poorconnection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of vehicle Repair" procedure.
▶ Go to "Terminal and Connector Inspection"procedure.
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.
Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
Has a problem been found?
▶ Repair as necessary and go to "Verification of vehicle Repair" procedure.
▶ Go to "Knock sensor circuit inspection" procedure.
Check Short to Voltage in signal circuit.
Key "OFF".
Disconnect Knock sensor connector.
Key "ON" ＆ ENG "OFF".
Measure the voltage between terminal 1 of knock sensor harness connector and chassis ground.
Specification : Approx 0V
Is the measured voltage within specification?
▶ Go to "Check Short to ground in signal circuit" procedure.
▶ Repair Short to Power in signal circuit and then, go to "Verification of Vehicle Repair" procedure.
Check Shrot to ground in signal circuit.
Key "OFF".
Disconnect Knock sensor connector and ECM connector.
Measure the resistance between terminal 1 and 2 of knock sensor harness connector.
Specification : Infinite
Is the measured resistance within specifications?
▶ Go to "Check Open in signal circuit" procedure.
▶ Repair Short to ground in signal circuit and then, go to "Verification of Vehicle Repair" procedure.
Check Open in signal circuit
Key "OFF".
Disconnect Knock sensor connector and ECM connector.
Measure the resistance between terminal 1 of knock sensor harness connector and terminal 19of ECM harness connector.
Specification : Below 1Ω
Is the measured resistance within specifications?
▶ Go to "Check Open in ground circuit" procedure.
▶ Repair Open in signal circuit and then, go to "Verification of Vehicle Repair" procedure.
Check Open in ground circuit.
Key "OFF".
Disconnect Knock sensor connector and ECM connector.
Measure the resistance between terminal 2 of knock sensor harness connector and ground.
Specification : Below 1Ω
Is the measured resistance within specifications ?
▶ Go to "Component inspection" procedure.
▶ Repair Open in ground circuit and then, go to "Verification of Vehicle Repair" procedure.
Check Knock sensor.
Substitute with a known - good Knock sensor and check for proper operation.
Is the signal normal?
▶ Replace Knock sensor and go to "Verification of Vehicle Repair" procedure.
▶ Substitute with a known - good ECM and check for proper operation.
▶ If the problem is corrected, replace ECM and go to "Verification of Vehicle Repair" procedure.
After a repair, it is essential to verify that the fault has been corrected.
Connect scan tool and select "Diagnostic Trouble Codes(DTCs)" mode.
Clear the DTCs and Operate the vehicle within DTC Enable conditions in General information.
Are any DTCs present ?
▶ Go to the applicable troubleshooting procedure.
▶ System is performing to specification at this time.
