Oxygen (O2) Sensor (2-Wire)

On all models, warm engine until coolant temperature is 185-205°F (85-96°C). Disconnect O2 sensor connector. See Fig 1 .
Connect digital voltmeter between terminal No. 1 and ground. Repeatedly race engine and observe O2 sensor output voltage. If output is not 0.6-1.0 volt, replace O2 sensor.

Fig 1: O2 Sensor Connector Terminal ID (2-Wire)
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.