2008 LR3 with codes: P0441 & p0420

philwas2 · Jun 15, 2017

I am finally getting somewhere with this. I had a mechanic (NOT the dealer but a local rover specialist) run a full diagnostic and he ignored any codes until he watched what the vehicle was actually doing via his "scan-tool."
I was told the only thing that came up was the catalytic converter-due to O2 sensor switching. The code P441 was not apparent . I asked about vacuum leeks and was told the vehicle didn't show signs of a vacuum leak.

SO, the question now is: does anyone have experience with MagnaFlow coverters? They seem to be more realistically priced then OEM. Are there other options I should be aware of?

ERover82 · Jun 15, 2017

I wonder if the cats are fine, but more emissions are entering the exhaust from incomplete combustion, such as old plugs or something?

Colin hughes · Jun 15, 2017

I have the cat efficiency codes come up every winter. I even replaced one cat last summer. Once spring arrives, the CEL light and the codes go away. I think up here in Canada it has something to do with the additives in the winter gas and the ethanol content making the truck run richer. The light hasn't come on for over a month now.

philwas2 · Jun 15, 2017

I was told that the incorrect switching of the O2 sensors- one before the cat and one after, indicates there is no change in concentration of noxious gasses after the exhaust exits the cats. I am looking for anything to look at before I replace the $1200cats on this truck!

I was excited to find magnaflow cats that are a direct fit. I am sure some don't like the brand for their reasons, but I believe they are respected as products that work. I just want/ NEED this light to go out! Currently, the car runs fine.

I feel I should mention I reside in a state that requires no inspection..... anyone ?

jymmiejamz · Jun 16, 2017

Do those cats have a warranty? I factory replacement is very unlikely to fail a second time. I haven't had great luck with aftermarket cats, but if they have a good warranty and the price is right, I say go for it.

discostew · Jun 18, 2017

EricTyrrell said:
I wonder if the cats are fine, but more emissions are entering the exhaust from incomplete combustion, such as old plugs or something?

That's the one code that pretty much only means the converter is bad. It neeeds 2 good o2 sensors to run the test. If anything else would cause it it would be an exhaust leak. Even a small one near the cat

discostew · Jun 18, 2017

What about a used one?

disco_drum · Jun 27, 2017

BDKR said:
I would definitely address the evap issue first. Clear codes then see if the code for the cat comes back.

@Shoggin. I normally do a top end clean with Seafoam on my cars. Haven't yet on the LR3 but the old lady is usually in it. I think I'll have a shot this weekend.

I forgot this from earlier....

https://www.youtube.com/watch?v=Dfj-F_pTj5M

This vid is pretty silly but it helped me with evap issues on my 850R and 323i.

https://www.youtube.com/watch?v=YFT-TVET_Qs

philwas2 · Aug 15, 2017

follow up

Here's a follow up on my cat issue and eventual replacement. I went with the Magnaflow OEM grade, direct-fit replacement Prt# 49719 and had my independent mechanic install it along with the O2 sensors. We decided to ignore the evap code and all has been well for over a month.
The converter comes with a 5yr warranty, so we'll see how they stand behind their product.

squirt · Aug 15, 2017

For anyone looking to solve a cat efficiency code in the future, rear O2 spacers will often eliminate the code. They make special versions with mini-cats and 90deg angles these days, but I used to use modified spark arrestors before that was an option. 9 times out of 10, the cat has lost efficiency, but tailpipe measurements are still within spec. No need to spend hundreds of dollars on a new cat to clear a code that can be solved for <$20 in parts. Note that I've done this on 4-5 vehicles over the years, and never had an issue with passing CA smog inspection.

WeBeCinYa · Aug 15, 2017

squirt said:
For anyone looking to solve a cat efficiency code in the future, rear O2 spacers will often eliminate the code. They make special versions with mini-cats and 90deg angles these days, but I used to use modified spark arrestors before that was an option. 9 times out of 10, the cat has lost efficiency, but tailpipe measurements are still within spec. No need to spend hundreds of dollars on a new cat to clear a code that can be solved for <$20 in parts. Note that I've done this on 4-5 vehicles over the years, and never had an issue with passing CA smog inspection.

Good info just in case, but what do you mean by O2 spacers?

squirt · Aug 15, 2017

WeBeCinYa said:
Good info just in case, but what do you mean by O2 spacers?

Search on eBay, and you'll have have about a million examples. It's basically a fitting that pulls the head of the sensor out of the main exhaust flow.

jwest · Aug 21, 2017

philwas2 said:
I was told that the incorrect switching of the O2 sensors- one before the cat and one after, indicates there is no change in concentration of noxious gasses after the exhaust exits the cats. I am looking for anything to look at before I replace the $1200cats on this truck!

I was excited to find magnaflow cats that are a direct fit. I am sure some don't like the brand for their reasons, but I believe they are respected as products that work. I just want/ NEED this light to go out! Currently, the car runs fine.

I feel I should mention I reside in a state that requires no inspection..... anyone ?

I have the Magnaflow cats and they did not cure the bank 1 code or stop CEL from happening... However the grin factor offsets the annoyance of having to clear the CEL periodically. I Swear the full system resulted in a little more go power for passing.

jymmiejamz · Aug 21, 2017

jwest said:
I have the Magnaflow cats and they did not cure the bank 1 code or stop CEL from happening... However the grin factor offsets the annoyance of having to clear the CEL periodically. I Swear the full system resulted in a little more go power for passing.

You still get catalyst efficiency faults after replacing the cats?

Howski · Mar 18, 2021

Has anyone else run into P0420 issues? Unfortunately I’ve gotten it a few times over the past couple months. I’m going to do a Cataclean treatment which I’ve read about elsewhere. Anything else that should be looked at upstream of the cats? No other codes and the truck has been running smooth. I always run 93, though not always from the best gas stations, and run Techron fuel system cleaner through it pretty regularly. May not be connected but wanted to mention the last few times it’s shown up shortly after a fill up

jymmiejamz · Mar 19, 2021

Howski said:
Has anyone else run into P0420 issues? Unfortunately I’ve gotten it a few times over the past couple months. I’m going to do a Cataclean treatment which I’ve read about elsewhere. Anything else that should be looked at upstream of the cats? No other codes and the truck has been running smooth. I always run 93, though not always from the best gas stations, and run Techron fuel system cleaner through it pretty regularly. May not be connected but wanted to mention the last few times it’s shown up shortly after a fill up

Just about every LR3 has P0420 issues at some point in its relatively lifetime. The only fix is to replace the defective cat. You can install spacers on the rear oxygen sensors so that it won't set the fault (assuming you live somewhere without thorough inspections).

Howski · Mar 19, 2021

We have no emissions testing here so I can go the spacer route if it persists. In most cases does this result in notable loss of performance, fuel economy, etc?

jymmiejamz · Mar 19, 2021

No difference. That code is just saying the catalyst is not doing its job based on the readings from the rear o2 sensors.

Tugela · Mar 19, 2021

Thanks for the info on this thread, it's timely as my LR3 has just sprung the trifecta of 0420, 0441, and 0171.

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2008 LR3 with codes: P0441 & p0420

philwas2

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ERover82

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Colin hughes

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philwas2

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discostew

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philwas2

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squirt

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