The oxygen concentration sensor is equipped with a heater that maintains the sensor temperature within a certain range when the engine is running in all operating modes. Maintaining a certain sensor temperature allows the system to start up faster and operate in idle mode.
1. Disconnect the connector from the oxygen concentration sensor and connect a special tool (test wire harness) to the sensor connector (Fig. 6.28).
Fig. 6.28. Location of the oxygen concentration sensor
2. Make sure that the circuit is closed between contact 1 (red terminal of the test lead harness) and contact 3 (blue terminal of the test lead harness) of the oxygen concentration sensor connector (the resistance between the contacts is 11–18 ohms at a temperature of 20°C) (Fig. 6.29).
Fig. 6.29. Checking the conductivity between the contacts of the oxygen concentration sensor connector
3. If there is no conductivity, replace the oxygen concentration sensor.
4. Start and warm up the engine to a temperature of over 80°C.
5. Using wires with crocodile clips, connect contact 1 of the connector (red clip) to the positive terminal of the battery, and contact 3 of the connector (blue clip) to the negative terminal of the battery (Fig. 6.30).
Fig. 6.30. Using jumper wires to test the oxygen concentration sensor
Warning: Be very careful when connecting the wires to the battery terminals, as the oxygen sensor may be damaged if the wires are connected incorrectly.
6. Connect a digital voltmeter to terminals 2 (black terminal) and 4 (white terminal) and measure the output voltage of the oxygen concentration sensor by changing the engine speed.
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.