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HEATED OXYGEN SENSOR CHECK

When using Scan tool, observe HO2S reading. If values are unsatisfactory, or if Scan tool is not available, use the following procedure:
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* between terminal 1 (red clip of special tool) and terminal 3 (blue clip of special tool) on the heated oxygen sensor connector.

NOTE:
*: 11 - 18 Ohms at 20 °C (68 °F) ,
4.5 - 8.0 Ohms at 20 °C (68 °F)

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 1 (red clip) of the heated oxygen sensor connector to the battery (+) terminal and terminal 3 (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 2 (black clip) and terminal 4 (white clip).

7. While repeatedly racing the engine, measure the heated oxygen sensor output voltage.
8. If the sensor is defective, replace the heated oxygen sensor.

NOTE: For removal and installation of the heated oxygen sensor, refer to Exhaust Pipe and Main Muffler.