Fault P0420 EML with new lambda/cat

[Louis]

Replaced the Cat and lambda sensors on my 1.2 clio but I still have the fault code P0420 Catalyst system efficiency below threshold bank 1.
When I removed the sensors they were both different, but the ones I bought to replace it were the same however they were stated to be universal. Could this be where my issue is or is my cat just not efficient? I have 2 years warranty on my sensors, and 1 year on my cat so should be okay either way.

Thanks

 

[barnesautos]

Is it a genuine OE replacement cat or a Micky mouse one ?
Normally the Micky mouse cats are not efficient .
I'd be looking for a good 2nd hand OE cat and go from there.
The sensors should be ok .

 

[Louis]

Is it a genuine OE replacement cat or a Micky mouse one ?
Normally the Micky mouse cats are not efficient .
I'd be looking for a good 2nd hand OE cat and go from there.
The sensors should be ok .

It was a cat from Ebay yeah, but it has a year warranty, or it's meant to anyway. I've contacted the people who sold the sensors and will see what they say. I could try one of my old ones? OE cat was out of my price range to be honest! Didn't want 2nd hand as I'd replaced mine as the flexi was knackered and my thinking was any 2nd hand ones would be of the same ilk.

 

[barnesautos]

To be honest . If you look about for a good second hand cat , have a look inside and check the monolith cell , if it's not loose of blocked it should be a good to go 2nd hand option . Look up Renparts on eBay .

 

[Louis]

Well i've been in contact with both lambda sensor supplier and cat supplier. They're sending me out a new lambda sensor to try post cat, so will get that fitted and see if the fault comes back. Next port of call is a new cat under warranty, but will just wait for a reply from the seller. They seem nice and responsive enough anyway! Will keep this updated for anyone in the future who runs into problems.

Will P0420 being constantly turned off via diagnostics cause me any issues to my clio? I still have good MPG etc.