The Cleaning Method For Oxygen Sensors Is As Follows:

Remove the oxygen sensor and add an excess of hydrochloric acid to a 5-10% ferric chloride solution, depending on the surface condition of the sensor head. Soak the oxygen sensor in a solution for 10-15 minutes, then remove it and rinse it with water. The surrounding four holes should be unobstructed, and when viewed from the bottom, the carrier inside should turn white after washing.
If the cleaning is not satisfactory, continue with this work until the white carrier can be seen.
After rinsing with water, install the sensor and repeat the fourth measurement step above. Generally speaking, as long as the sensor is not from a secondary factory, as long as the internal ceramic body is not cracked and the heating resistor is not open circuit, the oxygen sensor that has been cleaned as mentioned above can resume normal operation.