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 Circuit Inspection" procedure.

Ignition "OFF".

Disconnect HO2S sensor connecto.

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 HO2S

Especially check for "10A Sensor fuse" is installed and not blown.

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

Check for open in control harness.

(3)

Measure resistance between terminals 4 of the HO2S heater harness connector and 9 of the PCM harness connector.

Specification : Approx 0Ω

Check for short to ground in control circuit.

(1)

Measure resistance between terminal 4 of the HO2S heater harness connector and chassis ground.

Specification : infinite