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" & Disconnect HO2S(S2) connector.

Disconnect HO2S(S2) connector and ECM connector.

Measure the resistance between signal terminal of HO2S(S2) harness connector and HO2S(S2) signal terminal of ECM harness connector.

Is the measured voltage within specification?

	▶ Go to "Ground Circuit Inspection" procedure.
	▶ Repair or replace as necessary and then, go to "Verification of Vehicle Repair" procedure.

IG "OFF" & Disconnect HO2S(S2) connector.

IG "ON" & ENG "OFF".

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

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.