4.
Measure voltage between terminal 3 of the HO2S heater harness connector and chassis ground.
a.
Specification : Approx. B+
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?
YES
▶ Repair as necessary and go to "Verification of Vehicle Repair" procedure.
NO
▶ Go to "Power Supply Circuit Inspection" procedure.
Ignition "OFF".
Disconnect HO2S connector.
Ignition "ON" & Engine "OFF".
Measure voltage between terminal 3 of the HO2S heater harness connector and chassis ground.
Specification : Approx. B+
Is voltage within the specification?
YES
▶ Go to "Control Circuit Inspection" procedure.
NO
▶ Check for an open in the power supply circuit between the main relay and the Injector.
Especially check for "10A O2 Sensor fuse" is installed and not blown.
Repair as necessary and go to "Verification of Vehicle Repair" procedure.
Check for open in control harness
Ignition "OFF".
Disconnect ECM connector
Measure resistance between terminals 4 of the HO2S heater harness connector and 1 of the ECM harness connector.
Specification : Approx. 0Ω
Is resistance within the specification?
YES
▶ Go to next step as below.
NO
▶ Repair as necessary and go to "Verification of Vehicle Repair" procedure.
Check for short to ground in control circuit.
Measure resistance between terminal 4 of the HO2S heater harness connector and chassis ground.
Specification : infinite
Is resistance within the specification?
YES
▶ Go to "Component Inspection" procedure.
NO
▶ Repair as necessary and go to "Verification of Vehicle Repair" procedure.
