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.
Check voltage
Ignition "OFF"
Disconnect HO2 sensor connector
Ignition "ON" & Engine "OFF"
Measure voltage between terminal 3 of HO2S sensor harness connector and chassis ground.
Specification : Approx. B+
Is the measured voltage within specifications?
YES
▶ Go to " Control Circuit Inspection" procedure.
NO
▶ Check for open or short to ground in harness between main relay and HO2S and go to "verification Vehicle Repair" procedure.
Check for open in harness
Ignition "OFF"
Disconnect HO2 sensor connector and PCM connector
Measure resistance between terminal 4 of HO2 sensor harness connector and terminal 3 of PCM harness connector.
Specification : Approx. below 1Ω
Is the measured resistance within specifications?
YES
▶ Go to " Check for short to ground in harness " procedure.
NO
▶ Repair or replace as necessary and then, go to " Verification of Vehicle Repair " procedure.
Check for short to ground in harness
Ignition "OFF"
Disconnect HO2 sensor connector
Measure resistance between terminal 4 of HO2 sensor harness connector and chassis ground.
Specification : Infinite
Is the the measured resistance within specification?
YES
▶ Go to " Component Inspection " procedure.
NO
▶ Repair or replace as necessary. And then, go to " Verification of Vehicle Repair" procedure.
