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1. Disconnect the heated oxygen sensor connector and connect the special tool (test harness) to the connector on the heated oxygen sensor side.
2. Make sure that there is continuity [Approx. 12 Ohms at 20°C (68°F)] between terminal 2 (red clip of special tool) and terminal 4 (blue clip of special tool) on the heated oxygen sensor connector.
3. If there is no continuity, replace the heated oxygen sensor.
4. Warm up the engine until engine coolant is 80°C (176°F) or higher.
5. Use the jumper wires to connect terminal 2 (red clip) of the heated oxygen sensor connector to the battery (+) terminal and terminal 4 (blue clip) to the battery (-) terminal.

CAUTION: Be very careful when connecting the jumper wires; incorrect connection can damage the heated oxygen sensor.

6. Connect a digital Voltage meter between terminal 1 (black clip) and terminal 3 (white clip).
7. While repeatedly racing the engine, output Voltage should be 0.6 - 1.0 Volt.

NOTE: If you make the air/fuel ratio rich by racing the engine repeatedly, a normal heated oxygen sensor will output a Voltage of 0.6 - 1.0 Volt.

8. If the sensor is defective, replace the heated oxygen sensor.