4. The resistance wire of the heater is burnt out
For a heated oxygen sensor, if the resistance wire of the heater burns out, it is difficult for the sensor to reach normal operating temperature and lose its function.
5. The internal wiring of the oxygen sensor is disconnected.
Inspection of appearance color of 6 oxygen sensors
Remove the oxygen sensor from the exhaust pipe and check if the vent hole on the sensor housing is blocked and if the ceramic core is damaged. If there is any damage, the oxygen sensor should be replaced.
By observing the color of the top part of the oxygen sensor, the fault can also be determined:
① Light gray top: This is the normal color of the oxygen sensor;
② White tip: caused by silicon pollution, the oxygen sensor must be replaced at this time;
③ Brown tip: caused by lead pollution, if severe, the oxygen sensor must also be replaced;
④ Black tip: caused by carbon deposits, after troubleshooting the engine's carbon deposits, the carbon deposits on the oxygen sensor can generally be automatically removed.
The main oxygen sensor includes a heating rod for heating zirconia elements, which is controlled by an ECU computer. When the air intake is small (exhaust temperature is low), the current flows to the heating rod to heat the sensor, enabling accurate detection of oxygen concentration.
Platinum electrodes are installed on both sides of the ZRO2 element in a test tube. To protect the platinum electrodes, the outer side of the motor is covered with ceramics. The oxygen concentration input on the inner side is higher than that of the atmosphere, while the oxygen concentration input on the outer side is lower than that of the exhaust gas from the car.
It should be pointed out that after using a three-way catalytic converter, lead-free gasoline must be used, otherwise the three-way catalytic converter and oxygen sensor will quickly fail. Furthermore, it should be noted that the oxygen sensor plays a crucial role in stabilizing the throttle and preparing a standard mixture. However, during frequent enrichment or dilution of the mixture, the (ECU) computer will ignore the information from the oxygen sensor, rendering it ineffective.
Rear oxygen sensor
Currently, vehicles are equipped with two oxygen sensors, one in front of the three-way catalytic converter and one in the back. The front function is to detect the air-fuel ratio of the engine under different operating conditions, while the computer adjusts the fuel injection amount and calculates the ignition time based on this signal. The main task behind is to check the performance of the three-way catalytic converter! The conversion rate of the catalyst. Comparing the data with the front oxygen sensor is an important basis for detecting whether the three-way catalytic converter is working properly (good or bad)