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 "Control Circuit Inspection" procedure.
Check for open in control harness
Ignition "OFF".
Disconnect HO2S and ECM connectors.
Measure resistance between terminals 4 of the HO2S heater harness connector and 7 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 power in control circuit.
Reconnect the ECM connector.
Ignition "ON" & Engine "OFF".
Measure voltage between terminal 4 of the HO2S heater harness connector and chassis ground.
Specification : Approx. 0V
Is voltage within the specification?
YES
▶ Go to "Component Inspection" procedure.
NO
▶ Repair as necessary and go to "Verification of Vehicle Repair" procedure.
