Pug 208 - Catylist fault.

[chase]

Hi All ,
New on here but hello to you all .
The car is 208 active 1.2 petrol 2013 - 35k miles .
My Daughters car has the following fault code - P0420 - Catalyst efficiency below threshold. There are no other codes .
How to proceed .
1/ Try a cleaner for the CAT .
2/ Look elsewhere for the fault e.g. pre or post sensors on the Cat .
3/ Change the Cat .

Your advice/opinions welcomed .

chase

[xantia_v6]

If the car has a history of always being driven gently, it might be worth giving it a run at speed to get the cat as hot as possible to burn off a few accumulated impurities.
It could also be that one of the lamda sensors (I presume that there are 2 on this car) is getting lazy and giving the ECU incorrect data

[ekjdm14]

I would agree, it's likely either an O2 sensor (probably post-cat IMO), the wiring for them or it needs an "Italian tune up"

[chase]

My Daughter drives it like she stole it .
Discs worn out and 2 sets of pads ! in 30k miles.
Sensors ect - thoughts please .

[RichardW]

You need to get it on a diag machine that can read live data to see what the ECU is seeing from the downstream Lambda sensor. You can check the CAT is working with an infrared thermometer - there should be a significant increase in temp across the CAT if it is working. Seems unlikely a cat would fail on a 3 year old car, but sometimes these things happen. Really you would want to scope the sensor before replacing, but if the cat checks out and diag info shows the sensor not working, then taking a punt on replacing it is probably worth a shot.

[xantia_v6]

In this case, it would also be worth getting the exhaust checked with a proper gas analyser, as that, alsong with simultaneous lambda readings should definitively tell you whether the cat is working.

[CitroJim]

My Daughter drives it like she stole it

Only way to drive 2 series pugs with little engines It's great fun!

I do the same with my 207... Totally out of character for me but I love it so I can understand why your daughter does...

[ekjdm14]

My Daughter drives it like she stole it

Only way to drive 2 series pugs with little engines It's great fun!

I do the same with my 207... Totally out of character for me but I love it so I can understand why your daughter does...

I have to concur, even the 1.4HDi likes to be driven hard, could even say it DISlikes being treated like a diesel in fact! Given the way it's driven then less likely to be bunged up internally at least.

[chase]

Well so far the fault has stayed away after completing the following - Put some cat cleaner in the fuel tank (I don't know if it works but its cheaper than a sensor or Cat ) I then replaced the lower Oxygen sensor with the cheapest 1 I could get off ebay .
That was 10 days ago and still no fault back (I know its early yet ) but prior to doing this work the fault would recur on the second day after erasing the fault code .
Fingers crossed .

[CitroJim]

Good to hear all is now good but...

My experience with those very cheap eBay oxygen sensors is they often have a very short life...

[rotra]

For 208 and 206 the exhaust flex pipe in the Sonic takes a lot of abuse being so near the roadway/ground and rust apart causing the sensors throw this P0420 code (https://p0420.net/peugeot-208).