Warning! The sensors are installed near the catalytic converter, which heats up to a high temperature when the engine is running. To avoid burns, check the oxygen concentration sensors and remove them after the engine has cooled to a safe temperature.
To complete the work you will need:
- multimeter (in voltmeter mode);
- inspection ditch or overpass (to remove the lower sensor);
- special key for oxygen sensor.
Examination
1. Prepare the car for work (see "Preparing the car for maintenance and repair").
2. Disconnect the wiring harness connector from the oxygen concentration sensor connector.
3. Connect the negative probe of the voltmeter to the engine ground. After turning on the ignition, we check the supply voltage of the heating element at terminal B (the terminal designations are marked on the wiring harness block).
Note: The voltage at the terminal must be at least 12 V. If the voltage does not reach the terminal or is less than 12 V, the battery is discharged, the power supply circuit is faulty, or the electronic control unit is faulty.
4. Having connected the "minus" probe of the voltmeter to terminal C, we measure the voltage between terminals A and C.
Note: The voltage at the terminals should be 0.45 V. If the voltage does not reach the connector or it differs by more than 0.02 V, then the power supply circuit is faulty or the ECU is faulty.
Removal
1. Remove the oxygen concentration sensor wire holder from the opening in the protective screen.
2. Using a 22 mm wrench, unscrew the sensor from the catalytic collector and remove the sensor.
Note: A special key is required to unscrew the lower sensor. If such a key is not available (see "Tools, accessories and operating materials") you can cut off the handle of a regular 22 mm open-end wrench. If necessary, the lower sensor can be unscrewed from the removed catalytic collector.
Advice: You can verify that the sensor is faulty by replacing it with a known good one.
Installation
We install the sensor in the reverse order of removal.