Oxygen Sensor: Testing and Inspection

CIRCUIT DIAGRAM





INSPECTION USING SCAN TOOL





HARNESS INSPECTION PROCEDURE

COMPONENT TEST PROCEDURE

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













1. Disconnect the oxygen sensor connector, and measure the resistance between terminal 3 and terminal 4.

Standard value: 30 Ohms or more at 400°C (752°F)

2. Replace the oxygen sensor if there is malfunction.

3. Apply battery voltage directly between terminal 3 and terminal 4.

NOTE: Take care when applying the voltage, damage will result if the terminals are incorrect or are short circuited.

4. Connect a digital-type voltmeter between terminal 1 and terminal 2.

5. While repeatedly racing the engine, measure the oxygen sensor output voltage.

Engine Racing: Minimum 0.6 Volts

NOTE: Makes the air/fuel mixture rich by increased engine speed.

6. If there is a problem, it is probable that there is a malfunction of the oxygen sensor.

Oxygen sensor torque: 40-50 Nm (29-36 ft lb)