Montero LS 4WD V6-2972cc 3.0L SOHC 12 Valve (1994)
Oxygen Sensor: Testing and Inspection
1. Disconnect the connector to the heated oxygen sensor, then use the special tool (test harness) to make connections with the connection on the
heated oxygen sensor side.
2. Check that there is continuity between terminal (1) (black clip of the special tool) and terminal (3) (white clip) of the heated oxygen sensor
connector [approx. 2O Ohms at a temperature of 20°C (68°F) ].
3. If there is no continuity, replace the heated oxygen sensor.
4. Warm up the engine until the coolant temperature is 80°C (176°F) or higher.
5. Using jumper wires, connect terminal (1) (black clip of the special tool) and terminal (3) (white clip) of the heated oxygen sensor with the positive
battery terminal and negative battery terminal respectively.
CAUTION: When connecting the jumper wires, be careful not to connect them to the wrong terminals, since this could damage the heated
oxygen sensor.
6. Connect a digital voltmeter to terminal (2) (red clip of the special tool) and terminal (4) (blue clip).
7. While repeatedly racing the engine, measure the heated oxygen sensor's output voltage.
8. If the measurements are not as specified, the cause is probably a malfunction of the heated oxygen sensor.