Many malfunctions in the electrical system are caused by poor harness(es) 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".

Disconnect Knock sensor connector.

IG "ON" & ENG "OFF".

Measure the voltage between signal1 terminal of knock sensor harness connector and chassis ground.

Measure the voltage between signal2 terminal of knock sensor harness connector and chassis ground.

Is the measured voltage within specification?

	▶ Go to "Check Short in signal circuit" procedure.
	▶ Repair or replace as necessary and then, go to "Verification of Vehicle Repair" procedure.

IG "OFF".

Disconnect Knock sensor connector and ECM connector.

Measure the resistance between signal1 and signal2 terminal of knock sensor harness connector.

Is the measured resistance within specification?

	▶ Go to "Component inspection" procedure.
	▶ Repair or replace as necessary and then, go to "Verification of Vehicle Repair" procedure.