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 KEY "OFF".

Disconnect HO2S(S2)_DOWN connector.

IG KEY "ON" & ENG "OFF"

Measure the voltage between signal terminal "1" of HO2S(S2)_DOWN harness connector and chassis ground.

Is the measured voltage within specification ?

	▶ Go to "Ground Circuit Inspection" procedure.
	▶ Repair Open or Short circuit and then, go to "Verification of Vehicle Repair" procedure.

IG KEY "OFF".

Disconnect HO2S(S2)_DOWN connector.

Measure resistance between ground terminal of HO2S(S2)_DOWN and chassis ground.

Is the measured resistance within specification ?

	▶ Go to "Component Inspection" procedure.
	▶ Repair Open circuit and then, go to "Verification of Vehicle Repair" procedure.