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?

YES

▶ Repair as necessary and go to "Verification of Vehicle Repair" procedure

NO

▶ Go to " Power Circuit Inspection " procedure

IG "OFF" & Disconnect HO2S(B1/S2) connector.

IG "ON" & ENG "OFF".

Measure voltage between terminal 1 of HO2S(B1/S2) harness connector and chassis ground.

Specification : B+

Is the measured voltage within specification ?

YES

▶ Go to HO2S(B1/S2) heater "Control Circuit Inspection" procedure.

NO

▶ Repair open or short to ground in HO2S(B1/S2) Heater power circuit then, go to "Verification of Vehicle Repair" procedure.

IG "OFF" & disconnect HO2S(B1/S2) connector.

IG "ON" & ENG "OFF".

Measure voltage between terminal 2 of HO2S(B1/S2) harness connector and chassis ground.

Specification : Approx. 0 V

Is the measured voltage within specification ?

YES

▶ Go to HO2S(B1/S2) "Component Inspection" procedure.

NO

▶ Repair short to battery in HO2S (B1/S2) heater control circuit and go to "Verification of Vehicle Repair" procedure.