Citroen C3 1.4 Gasoline + LPG: Catalytic Converter Aging - Error P0420 Reoccurrence

Question

Hello to all Electrode Members. This is my first post, due to the fact that I can not find an answer to my questions. The fault concerns the car: Citroen C3 2002 engine 1.4 petrol (KFV) Error P0420 - catalyst aging. Short description. Half a year ago in December 2016, the check engine indicator...

Anonymous · Accepted Answer

The first probe influences the composition of the mixture the second is a diagnostic probe, checks the correctness of the first action and the work of the catalyst ...

Maybe it is some leakage at the connection of the catalyst with the exhaust manifold ... Was the gasket replaced with the catalyst? It would be good to unscrew the catalyst and connect the joint with a paste to seal the exhaust system, previously cleaning the contact surfaces of both components.

sebap · Accepted Answer

Record the film from the work of the probes and upload here.

Anonymous · Accepted Answer

I had a case with a peugeot 208 1,2. The error is identical, the operation of the probe behind the catalyst is almost identical to that before, i.e. either the second one is freaking out or the catalyst is damaged. After removing the cover, it turned out that the catalyst housing was bursting with temperature and fresh air was supplied to the exhaust gases (and the lambda probe is responsible for the measurement of oxygen in the exhaust gases), hence the anomalies on the second probe ...
It is also possible to exclude damage to the probe, it is only strange that the problem has disappeared for half a year.

Anonymous · Accepted Answer

The first lambda probe shows the correct values; it is best to check it in graphical form, where the voltage fluctuation graph should oscillate between 100mV - 900mV
The second probe with an efficient catalytic converter should indicate 400mV to 600mV; it has to be taken into account that the probe has very hard working conditions and the ceramics are aging, which may cause delays in signal transmission.
On the attached materials, the second probe gives the indications very close to the first one alternating, which results from the time needed for gas flow between the two probes.
The latter certainly does not work properly; check resistance of the heater and voltage on the plug.
Previously, I sent the values of correct indications;
If the exhaust gas analysis did not detect any abnormalities and the catalytic converter works properly (and it needs oxygen to work properly), then after replacing the probe, everything should return to normal.
you can buy something on the sidestream as long as the price is not frightening ... or if the plugs of both probes are identical, the swap should also bring something.

By the way, the catalyst is damaged when gasoline enters the exhaust system along with the exhaust gas; several reasons; pours the injection, unburnt fuel / air mixture, etc. In the exhaust gas you can feel the petrol.
I wonder if sometimes it is not the fault of the second probe from the beginning, and the new catalyst improved slightly the voltage indication sent as a signal to the ECU.

orzech1988 · Answer

Honestly, I have no idea if the catalyst was exchanged according to the art and whether the gasket was replaced. I left the car with a mechanic who had good reviews, and if I did it well, I do not know. For half a year it was all right. I will try to see the connection you mentioned in a short time. Perhaps there is a leak there. Thank you for your help. Any additional suggestions from forum members are welcome.

orzech1988 · Answer

I tried to upload, but it only takes a few seconds ... And the movie has been reduced from 101 MB to about 22 MB. In the first post at the very end I gave youtube links. You only have to delete the stars in the link, otherwise I could not paste. Added after 2 [minutes]: It may have been that the catalyst was previously damaged, after the replacement of the new one, in turn, the probe broke. Unhappiness goes in pairs. But for the moment I am inclined to this left air and some leakage.

orzech1988 · Answer

It's like this: I got tired of the jack and pushed under the car. Below is a pictorial photo of combining a kata with a collector. It looks like the exchange is okay, I have heard nothing, and I have not felt any leaks. In the pictures you can see a mass, perhaps the sealer you mentioned. I did not see any cracks or anything on the catalytic converter and in the vicinity. I shot the photo probe as in the picture. It seems to be a bit tired. but up to shore ... I measured the resistance of the heater, i.e. unplugged the plug and measured the resistance between the two white wires. I am not an electronics or mechanic, so I attach pictures as I set up the Multimeter. The resistance was 7.6 Oma, if I read correctly. Should it ?? 15 -30 ohms? So it means that the probe is 99% damaged? Regarding the voltage, I measured it: on the motor switched on the second part of the plug I connected to the negative pole of the battery and the result was on one of the cables above 14 V, also the voltage is, if I understand correctly. The conclusion is as follows: replacing the Lambda probe, do I understand correctly? Added after 2 [minutes]: This knowledge will also be useful in the future. It is very possible that you are right and the catalyst was fairly efficient. I'll see how I change the probe and leave the whole tank. Will the error no longer jump out.

Anonymous · Answer

Leakage is rather difficult to find if it is small, the simplest way is clogging the exhaust outlet in the final silencer (taking into account the high temperature of the exhaust), in the case of a tight system the engine will choke and go out, and in the case of leaks hissing. In the case of small leaks, one person is not enough, and excess gases that do not have an outlet can also suppress the engine which will give an incorrect result on the system (and NEVER completely clog the outlet pipe, in the best case you can blow out the gaskets). It is best to cover the gas outlet so that the engine works all the time and to create a sufficiently high pressure of the exhaust gases so that excess gases escape through the leak, the other person is best able to inspect the system from the collector to the end of the system.

In the case of an exhalation system, exhaust gases do not necessarily have an outlet at a leak, and the exhaust gas pressure can create a negative pressure, eg at the joints that have not been thoroughly cleaned, and pull up fresh oxygenated air giving an incorrect result on the second probe.
That's how it looks from theory.
The pictures show a professional work (there is a seal, there is a sealing paste), which is uncertain for the diagnosis.

Multimeter set correctly, resistance indication also.
Results which should be shown by measurements for
Probe in front of the catalyst

Behind the catalyst

Data refer to the KFV (TU3JP) engine
As the probes are the same, to eliminate damage to one of them, it is worthwhile to omit them in places. They differ slightly in the resistance of the heater, but this should not have a significant effect on the result.

orzech1988 · Answer

Probe replaced with new one, erased errors ...
Now I drive and see if the error will appear again or not.

Attached photos and video.

MOVIE:
please delete "****" stars
www. ****** ****** youtube. com / watch? v = pxYNTG_yfXQ

Added after 3 [minutes]:

I still have a question, unrelated to the topic, and I do not want to throw it elsewhere.

What are the elements marked on the picture (PDF), what are they used for, what are they responsible for?

Thank you in advance for your answer.

Anonymous · Answer

This is a secondary air system to oxygenate the exhaust; Here you will learn how it works and how to diagnose

orzech1988 · Answer

Thanks for your quick response! It's good to know what this equipment is, because I never knew what it was.

orzech1988 · Answer

I traveled a bit ... the error jumped again, despite the replacement of the probe behind the collector. Attached photos.
In addition, I was to measure the composition of the exhaust of the photo I also paste.

Any ideas what is wrong? How to fix the fault? Do you run the system and drive as it is?
Greetings.

Added after 2 [minutes]:

When it comes to photos from the exhaust gas analysis, this is the first picture about exhaust gas on gasoline. The second photo shows the analysis of LPG combustion.

Anonymous · Answer

I focused so much on the catalyst error that I overlooked the error regarding the secondary air system. I would start with the solution of this fault, and then it will be known what the catalyst.

Citroen C3 1.4 Gasoline + LPG: Catalytic Converter Aging - Error P0420 Reoccurrence

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