P0331

COMPONENT LOCATION





GENERAL DESCRIPTION

The knock sensor is attached to the cylinder block and senses engine knocking. The sensor contains a piezoelectric element that converts vibration (or noise) into voltage signal and sends this signal to ECM. With input signals from camshaft position and crankshaft position sensor, ECM can identify which cylinder is knocking. ECM filters vibrations and determines if the vibrations are knocking signal. The Engine Control Module (ECM) uses this signal to suppress knocking by retarding ignition timing. The ECM will set a code (Malfunction Indicator Lamp will Not turn on) if during two driving cycles the Knock sensor's output voltage falls below minimum threshold. This code indicates an unexpected vibration is being read by the Knock sensor or ECM under normal engine operation.

DTC DESCRIPTION

Checking the range of input signal with a knock sensor under detecting condition, ECM senses short in knock sensor circuit or malfunction of sensor. If the filtered knock signals are out of the threshold value. using standard duration, ECM sets P0331.

DTC DETECTING CONDITION





SCHEMATIC DIAGRAM





MONITOR DTC STATUS

1. Check DTC Status
(1) Connect scantool to Data Link Connector(DLC).
(2) IG "ON".
(3) Select "Diagnostic Trouble Codes(DTCs)" mode, and then Press F5(INFO) to check DTC's information from the DTCs menu.
(4) Read "DTC Status" parameter.




(5) Is "Present" Fault displayed?
YES
> Go to "Terminal and connector inspection" procedure.
NO
> Fault is intermittent caused by poor contact in the sensor's and/or ECM's connector or was repaired and ECM 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.

TERMINAL AND CONNECTOR INSPECTION

1. Many malfunctions in the electrical system are caused by poor harness and terminal condition. 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 short to battery in harness
(1) IG "OFF" and disconnect knock sensor connector.
(2) IG "ON" and ENG "OFF"
(3) Measure voltage between terminal 1 of knock sensor harness connector and chassis ground
(4) Measure voltage between terminal 2 of knock sensor harness connector and chassis ground.

Specification : Approx. 1.5V





(5) Is the measured voltage within specification?
YES
> Go to "Check short to ground in harness" as follows.
NO
> Repair short to battery in harness, and go to "Verification of Vehicle Repair" procedure.
2. Check short to ground in harness
(1) IG "OFF" and disconnect knock sensor connector and ECM connector.
(2) Measure resistance between terminal 1 of knock sensor harness connector and chassis ground.
(3) Measure resistance between terminal 2 of knock sensor harness connector and chassis ground.

Specification : Infinite





(4) 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 ECM. and then if the problem is corrected, replace ECM and go to "Verification of Vehicle Repair" procedure.
NO
> Repair short to ground 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 ECM. After testing ECM on the vehicle, use this function before reusing the ECM

VERIFICATION OF VEHICLE REPAIR

After a repair, it is essential to verify that the fault has been corrected.
1. Connect scan tool and select "Diagnostic Trouble Codes(DTCs)" mode
2. Press F5(INFO) and confirm that "DTC Readiness Flag" indicates "Complete". If not, drive the vehicle within conditions noted in the freeze frame data or enable conditions
3. Read "DTC Status" parameter
4. Is "History (Not Present)" fault displayed?
YES
> System performing to specification at this time. Clear the DTC
NO
> Go to the applicable troubleshooting procedure.