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 "Signal Circuit Inspection" procedure.

IG "OFF" and disconnect knock sensor connector.

IG "ON".

Measure voltage between low signal terminal of knock sensor harness connector and chassis ground.

Measure voltage between high signal terminal of knock sensor harness connector and chassis ground.

Is the measured voltage within specification ?

	▶ Go to "Check short to ground in harness" as follows.
	▶ Repair short to battery in harness, and go to "Verification of Vehicle Repair" procedure.

IG "OFF" and disconnect knock sensor connector and ECM connector.

Measure resistance between low signal terminal of knock sensor harness connector and chassis ground.

Measure resistance between high signal terminal of knock sensor harness connector and chassis ground.

Is the measured resistance within specification ?

▶ 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. note There is a memory reset function on scantool that can erase optional parts automatically detected and memorized by ECM. Before or after testing ECM on the vehicle, use this function to reuse the ECM on the others

▶ Repair short to ground in harness, and go to "Verification of Vehicle Repair" procedure.