13A-HEATED OXYGEN SENSOR CHECK

HEATED OXYGEN SENSOR CHECK

Required Special Tool:

Heated oxygen sensor (rear)

1. Disconnect the heated oxygen sensor (rear) connector and connect special tool MB991658 to the connector on the heated oxygen sensor (rear) side.

2. Measure the resistance between terminal No. 1 and terminal No. 2.

Standard value: 4.5 - 8.0 ohms [at 20 °C (68 °F)]

3. If the resistance deviates from standard value, replace the heated oxygen sensor (rear).

4. Warm up the engine until engine coolant is 80°C (176°F) or higher.

5. Drive at 50 km/h (31 mph) or more for 10 minutes.

6. Connect a digital voltage meter between terminal No. 3 and terminal No. 4.

7. Measure the output voltage of the heated oxygen sensor (rear) under the following driving.

Standard value:

HEATED OXYGEN SENSOR OUTPUT VOLTAGE	REMARKS
0.6 - 1.0 V	High load operation makes air/fuel ratio richer and normal heated oxygen sensor (rear) also can output voltage of 0.6 - 1.0 V.

note	If the temperature of sensing area does not reach the high temperature [of approximately 400°C (752°F) or more] even though the heated oxygen sensor (rear) is normal, the output voltage would be possibly low in spite of the rich air-fuel ratio.

note	When the vehicle is driven with high loads, the temperature of the sensing area of the heated oxygen sensor (rear) is sufficiently high. Thus, it is not necessary to apply the voltage to the heater.

8. If the output voltage is not within the standard value, replace the heated oxygen sensor (rear).

note	For removal and installation of the heated oxygen sensor (rear), refer to GROUP 15, Exhaust Pipe, Main Muffler And Catalytic Converter - Removal and Installation .