Front oxygen sensor
1. Disconnect the connector from the oxygen concentration sensor and connect a special tool to the connector on the side of the sensor (test lead harness) (pic. 7.6).
Pic. 7.6. Location of the oxygen concentration sensor
2. Verify that the circuit is closed between pin 1 (test lead harness red clip) and pin 3 (blue clip on test harness) front oxygen sensor connector (the resistance between the contacts is 4.5-8.0 Ohm at a temperature of 20°C) (pic. 7.7).
Pic. 7.7. Check of conductivity between contacts of a socket of the gauge of concentration of oxygen
3. If there is no continuity, replace the oxygen concentration sensor.
4. Start and warm up the engine to a temperature above 80°C.
5. Wires with crocodile clips connect pin 1 of the connector (red clip) with the positive terminal of the battery, and pin 3 of the connector (clip blue) with negative battery terminal (pic. 7.8).Be very careful when connecting the wires to the battery terminals, as if the wires are connected incorrectly, the oxygen concentration sensor may be damaged.
Pic. 7.8. Using connecting wires to test the oxygen concentration sensor
6. Connect a digital voltmeter to pins 2 (clip black) and 4 (clip white).
7. By changing the engine speed, measure the output voltage of the oxygen concentration sensor.
Oxygen concentration sensor output voltage: 0.6-1.0V
8. If the output voltage of the sensor differs from the required one, replace the sensor.
Rear oxygen sensor
1. Disconnect the connector from the rear oxygen sensor and connect the special tool to the connector on the sensor side (test lead harness) (pic. 7.9).
Pic. 7.9. Rear Oxygen Sensor Location
2. Verify that there is continuity between pin 3 and pin 4 of the oxygen sensor connector (the resistance between the contacts is 11-18 ohms at a temperature of 20°C) (pic. 7.10).
Pic. 7.10. Check of conductivity between contacts of a socket of the back gauge of concentration of oxygen.
3. If there is no continuity, replace the oxygen concentration sensor. If the MUT-II does not display nominal values despite previous resistance checks and wiring condition showing good condition, replace the oxygen sensor.