[S.Harding]

Hello everyone

2 weeks ago I replaced the catalytic converters on my R32 Mk5 as a hole in the flexi pipe let the car run rich for too long killing the catalytic converters.

After about 500 miles the engine management light reappeared. My Blue Driver OBD2 reader brought up these codes.

Any ideas? Is this a sensor or are the catalytic converters faulty?

Cheers

 

[Lucifer]

Did you replace the factory cat pipe system for a after market system with sport cats ?

 

[S.Harding]

Hello Lucifer. Thank you for your reply. I put a miltek stainless steel catalytic converter system on. I couldn't stomach £3000 for OEM ones.

 

[ChrisGR32]

I get the PO420 code pop up every 2 or 3 months. I've tried all the so called solutions for this, so just clear it and wait for it to reappear, in another couple of months. Do not worry about it, or spend loads of dough trying to fix it.

 

[S.Harding]

I get the PO420 code pop up every 2 or 3 months. I've tried all the so called solutions for this, so just clear it and wait for it to reappear, in another couple of months. Do not worry about it, or spend loads of dough trying to fix it.

Hello ChrisGR32. Thank you for your reply. I have cleared the code. I hope it is just a faulty sensor. I will keep an eye on it and see what happens.

 

[Mitch9894]

Hello ChrisGR32. Thank you for your reply. I have cleared the code. I hope it is just a faulty sensor. I will keep an eye on it and see what happens.

Hey, So as Lucifer pointed out, if you fitted the Milltek cats rather than OEM you will need to get the post cat O2 sensors coded out as the Milltek cats are a High Flow/Sport Catalytic converter (more noise, more power etc). Meaning they are less restrictive/less efficient and have more flow. So the O2 sensors are currently working fine and giving you a false positive because as far as they are concerned the efficiency is "below threshold".

 

[S.Harding]

Hey, So as Lucifer pointed out, if you fitted the Milltek cats rather than OEM you will need to get the post cat O2 sensors coded out as the Milltek cats are a High Flow/Sport Catalytic converter (more noise, more power etc). Meaning they are less restrictive/less efficient and have more flow. So the O2 sensors are currently working fine and giving you a false positive because as far as they are concerned the efficiency is "below threshold".

Hello Mitch9894. Thank you very much for your reply. This is most helpful. The engine light hasn't come back since. If it does, I will just have to clear it. Is it normal for it to run a little rich with sports cats attached? Sometimes it can smell like fuel from the exhausts on the occasion.
Cheers

 

[Mitch9894]

Hello Mitch9894. Thank you very much for your reply. This is most helpful. The engine light hasn't come back since. If it does, I will just have to clear it. Is it normal for it to run a little rich with sports cats attached? Sometimes it can smell like fuel from the exhausts on the occasion.
Cheers

Yea so in a perfect world you would get a tune done after the installation of sports cats to get the best out of them and disable the rear O2 sensors. Without a tune fuel smell is kinda to be expected.

 

[S.Harding]

Yea so in a perfect world you would get a tune done after the installation of sports cats to get the best out of them and disable the rear O2 sensors. Without a tune fuel smell is kinda to be expected.

Hello Mitch9894
Thank you very much for your help. I have never put an aftermarket component on a car before so this is a whole new world for me. I would prefer to go original but £3000 for OEM cats is too hard to swallow. I just hope the fuel smell won't kill the cats again.

Thanks Again 👍👍👍

 

[N3DXT]

Jumping in here as I had my cats fail recently and replaced them with a high flow Lucifer version (he was a lifesaver).

How easy is it to code out the O2 sensors, I don't know any local places that do reasonably priced maps, plus I'm reluctant to put anymore money into the car for the time being, I've had the car less than 4 months and its already relieved me of £7k, last owner sold it at the right time.