oxygen sensors common fault1. Oxygen sensor poisoning
Oxygen sensor poisoning is a common and difficult to prevent fault, especially for cars that often use leaded gasoline. Even a new oxygen sensor can only work for a few thousand kilometers. If it is only a slight lead poisoning, then use a box of unleaded gasoline to remove the lead on the surface of the oxygen sensor and restore it to normal operation. However, due to excessively high exhaust temperature, lead often invades its interior, hindering the diffusion of oxygen ions and making the oxygen sensor ineffective. At this time, it can only be replaced.
In addition, silicon poisoning of oxygen sensors is also common. Generally speaking, silicon dioxide generated by the combustion of silicon compounds contained in gasoline and lubricating oil, and silicone gas emitted by improper use of silicone rubber sealing gaskets will make oxygen sensors ineffective, so good quality fuel and lubricating oil should be used. When repairing, correctly select and install rubber gaskets, and do not apply solvents and anti-sticking agents other than those specified by the manufacturer to the sensor.
2. Carbon deposits
Due to poor engine combustion, carbon deposits are formed on the surface of the oxygen sensor, or oil or dust and other deposits enter the oxygen sensor, which will hinder or block the external air from entering the oxygen sensor, making the signal output by the oxygen sensor inaccurate, and the ECU cannot correct the air-fuel ratio in time. Carbon deposits are mainly manifested as increased fuel consumption and significantly increased emission concentration. At this time, if the deposits are removed, normal operation will be restored.
3. Oxygen sensor ceramic fracture
The ceramic of the oxygen sensor is hard and brittle. It may be broken and fail if it is hitten with a hard object or blown with a strong airflow. Therefore, when handling it be particularly careful and if you find a problem please replace it in time.
4. Heater resistor wire burns out
For heated oxygen sensors, if the heater resistor wire burns out, it is difficult for the sensor to reach the normal operating temperature and loses its function.
5. The internal circuit of the oxygen sensor is disconnected
6. Check the appearance color of the oxygen sensor
Remove the oxygen sensor from the exhaust pipe and check whether the vent hole on the sensor housing is blocked or whether the ceramic core is damaged. If it is damaged, the oxygen sensor should be replaced.
Front oxygen sensor rear oxygen sensorThe oxygen sensor in front of the three-way catalytic converter is called the front oxygen, and the rear oxygen is mounted after the three-way catalytic converter. It is generally considering that the front oxygen has a greater effect than the rear oxygen, because the front oxygen is used to adjust the density of the mixed gas, and the rear oxygen is to monitor the working condition of the three-way catalytic converter. Oxidation reaction will occur when the three-way catalytic converter is working, such as CO+02=CO2, which means that the oxygen content monitored by the rear oxygen is less than that of the front oxygen. Otherwise, the three-way fails or the purification capacity decreases, a few vehicles will light up the fault light, prompting the owner to check or replace the catalyst.
