1. Light gray tip: this is the normal color of the oxygen sensor.
2. White top: caused by silicon pollution, the oxygen sensor must be replaced at this time;
3. Brown top: caused by lead pollution, if serious, must also replace the oxygen sensor;
4. Black top: It is caused by carbon deposit. After removing the engine carbon deposit fault, the carbon deposit on the oxygen sensor can be automatically removed.
The main oxygen sensor includes a hot rod for heating the zirconia element. The heating rod is controlled by the (ECU) computer. When the air intake is small (the exhaust gas temperature is low), the current flows to the heating rod to heat the sensor, so that the oxygen concentration can be accurately detected.
On the inner and outer sides of the zirconium element (ZRO2) in the test tube, a platinum electrode is arranged. In order to protect the platinum electrode, the outside of the motor is covered with ceramic, the inner input oxygen concentration is higher than the atmosphere, and the outside input oxygen concentration is lower than the vehicle exhaust gas concentration. .
It should be noted that after the three-way catalytic converter, unleaded gasoline must be used, otherwise the three-way catalytic converter and the oxygen sensor will quickly fail. It is also important to note that the oxygen sensor is more important when the throttle is stable and is prepared for standard mixing. When the tank is frequently enriched or diluted, the (ECU) computer will ignore the oxygen sensor information and the oxygen sensor will not function.