Oxygen sensor failure lamp lights up repeatedly, and oxygen sensor failure analysis

Poisoning failure

Oxygen sensor poisoning can be said to be the most common failure phenomenon. It is also divided into two types: lead poisoning and silicon poisoning. The former is often found in cars that use leaded gasoline, and the latter is a silicon dioxide substance produced by the combustion of silicon compounds contained in gasoline and lubricating oil.

Then, we judge the fault by observing the color of the top part of the oxygen sensor (the normal color is light gray). If it is a white top, it means that the oxygen sensor has been contaminated with silicon to a certain degree and needs to be replaced in time. If it is brown, it is caused by lead contamination, and it must be replaced. But if it is a black top, it is mainly caused by carbon deposits, so you only need to clean it.

Ceramic fragmentation

The ceramic of the oxygen sensor is hard and brittle. It may be broken by hitting with a hard object or blowing with a strong airflow, causing the oxygen sensor to fail to maintain a normal working state. As for the judgment of the release method, first we have to remove the oxygen sensor from the exhaust pipe and check whether the vent on the sensor housing is blocked or the ceramic core is damaged. If it is really damaged, it will naturally need to be replaced with a new one.

Resistance wire burned

The heater resistance wire is burned. For a heated oxygen sensor, if the heater resistance wire is ablated, it is difficult to make the sensor reach the normal working temperature and lose its function.

Disconnected line

The internal circuit of the oxygen sensor is disconnected.

However, the two types of faults, wire-breaking and line disconnection, both require a professional fault detector to extract the data stream (the amplitude and frequency of the voltage change of the oxygen sensor). If the frequency is lower than 10 times per second, we can preliminarily determine that the oxygen sensor is malfunctioning. If the feedback voltage of the oxygen sensor does not change significantly at a voltage of 0.45V, it can basically be determined that the oxygen sensor has been damaged.