Oxygen Sensor: Testing and Inspection

HEATED OXYGEN SENSOR (HO2S) - II




CIRCUIT DIAGRAM










HARNESS INSPECTION PROCEDURE

SENSOR INSPECTION

NOTE:
(1) Before checking, warm up the engine until the engine coolant temperature reaches 80 to 95°C (176 to 205°F).
(2) Use an accurate digital voltmeter.

1. Replace the oxygen sensor if there is a malfunction.

Tightening torque: 50-60 Nm (37-44 ft.lbs.)










TROUBLESHOOTING PROCEDURE




TROUBLESHOOTING HINTS
When the lean/rich period is above 2.6 seconds in the condition that fully warm-up engine is 2,000 - 3,000 rpm and engine is above middle load.




USING VOLTMETER

NOTE: If you release the accelerator pedal suddenly with the engine running about 4000 rpm, the fuel supply will be stopped for a while. When you suddenly press the accelerator pedal, the voltage will reach 'B' range. Then, when you let the engine idle again, the voltage fluctuates between 'A' and 'B' range. In this case, the O2 sensor can be determined as good.