One of the error codes recorded in the ECM is P0420 which has a description indicating the poor efficiency of the catalytic converter, catalyst, installed in some exhaust sections near the manifold where the combustible gases are already exiting, they are responsible for reducing pollutant emissions.
Two oxygen sensors, including the catalyst.
The main function of the catalytic converter is to reduce the emissions of pollutants, since it is a vital component of reducing the environmental impact, it is equipped with a screen that allows evaluation of its effectiveness by generating an error code and lighting the engine fault indicator on the dashboard. Of tools.
This is the type of error code that can trigger a Check Engine or Service Engine, and quickly lights up permanently without the need for symptoms or modifications to the engine’s normal performance, and in some cases you may notice moments where you lose energy to the point of not being able to travel due to low acceleration However, these conditions are less frequent and are mainly due to knocks, overheating, or oil in the catalyst that ends up blocking the exhaust, reducing the power in the engine.
Sensor 1 and Sensor 2
As we know very well and have written in previous articles, the first oxygen sensor is responsible for monitoring whether the fuel mixture is rich or weak based on the amount of oxygen in the actually burning gases coming from the combustion chamber which was installed before the catalyst.
A second oxygen sensor is installed behind the catalyst and is intended to monitor the effectiveness of this component only.
What is the difference?
The waveform of the oxygen sensor The first sensor is used by the engine control unit (ECM) to correct the fuel delivery, in this way the No. 1 sensor will differ between the fat free mixture and the rich mixture, and this represents a variation in the voltage generation between. 250 and 1.0 volts.
Also Read: https://www.fixmycar.pk/catalytic-converter/
If the information from the sensor reflects the presence of a lean mixture, the ECM corrects the delivery by increasing it, once the information indicates that the mixture is now rich, the ECM corrects again by reducing the fuel delivery, this process is repeated to Indefinitely while the engine is running. Open. The engine control module (ECM) compares the information sent between sensor 1 and sensor 2 to determine the effectiveness of the catalyst
Sensor 2 waveform In the second sensor we see a different waveform, in the image we can see the signal from the first sensor as a red line and in the case of the second sensor, a blue line we see more stable with smaller oscillations than not. They had a capacity unlike that of the first oxygen sensor.
This is because in a catalyst operating efficiently there will not be the same difference in the amount of oxygen at the outlet of this component compared to the parameters presented at the input.
When the voltage transmitted by the second sensor is similar to that of the first oxygen sensor, error code P0420 can be recorded indicating that the efficiency of the catalyst is low, it is important to remember that when replacing the catalyst it must be installed in the same position between the two oxygen sensors, otherwise the check engine or service engine light will remain illuminated Permanently, and also in cases where the new component is not of good quality, he will be very sure that within days the code error recording will return.
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