P0420 / P0430 Code - Don't Replace Catalytic Converters, Try Induction Service

[SALEEN961]

My truck recently started throwing a P0430 code. When I cleared the code, it would routinely come back within one or two days. This happened across multiple tanks of fuel from different stations, so I knew that bad fuel wasn't the issue. I also know that my 25,000 mile truck has no maintenance issues, misfires, or oil consumption that would cause a catalyst failure, so there is no good reason for a catalyst to have actually failed.

I decided to run an induction service on my truck with about 32oz of water, followed by a polyetheramine based induction cleaner. Once that was done, I took my truck through a couple 1 hour catalyst reconditioning drive cycles where I would alternate between cruising at 70mph, aggressively accelerating from 30mph to 70mph, and coasting from 70mph to 60mph. In the end, no parts had to be replaced.

Here are the scan tool readings I had when the P0430 code was constantly returning:

Here are the scan tool readings after the induction service and drive cycles:

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[XLT22]

This only works for a little while. There have been off/on catalyst brick issues with the supplier going back to around 2018.

 

[SALEEN961]

This only works for a little while. There have been off/on catalyst brick issues with the supplier going back to around 2018.

I've been doing this at the shop I work at for a few years now, and so far we've had a 100% success rate. None of the vehicles have come back with a P0420 or P0430 code yet and some of them were so bad when they first came in that we thought trying to recondition the catalysts would be a complete waste of time.

These photos aren't cropped very well, but in the before photo, the bank 1 catalyst is just beyond the max allowable value. After running an induction cleaning service and taking the car on a 1 hour reconditioning drive cycle the numbers are significantly improved. This Land Rover was serviced in October 2024, and 13 months later the codes have not returned.

 

[tomcaudell]

The Ford dealer wouldn’t repair/replace bad Cat? I thought that they had a 100k warranty on all emission parts Fed mandated.

 

[Old Hat]

Do you have any idea what causes the codes? Thanks for posting.

 

[XLT22]

I've been doing this at the shop I work at for a few years now, and so far we've had a 100% success rate. None of the vehicles have come back with a P0420 or P0430 code yet and some of them were so bad when they first came in that we thought trying to recondition the catalysts would be a complete waste of time.

These photos aren't cropped very well, but in the before photo, the bank 1 catalyst is just beyond the max allowable value. After running an induction cleaning service and taking the car on a 1 hour reconditioning drive cycle the numbers are significantly improved. This Land Rover was serviced in October 2024, and 13 months later the codes have not returned.

This isn't a land rover issue, it's a Ford issue. Several TSBs have been issued since 2018 dealing with these two DTCs specifically referencing poor washcoating of the catalyst brick. Cleaning it won't work for long.

https://static.nhtsa.gov/odi/tsbs/2023/MC-10230765-0001.pdf

 

[Diligenthunter]

The Ford dealer wouldn’t repair/replace bad Cat? I thought that they had a 100k warranty on all emission parts Fed mandated.

Only 80k miles, sucks codes popped for me at 86k

I ended up buying spd high flow but found the issue in my case was actually a running livernios tune on an old strat code. Updated my pcm to most recent and had them update my tune and the issue went away for atleast a week before I ended up replacing with SPD.

From what I could see the cats looked perfect when I swapped them out.

 

[tomcaudell]

Thats the real cure.

 

[SALEEN961]

Do you have any idea what causes the codes? Thanks for posting.

In my case I would be willing to bet that excessive idling and short trip driving are the main issues. My commute to work is only 3.4 miles and I recently bought a house that is 2.1 miles from our current house, so my driving is mostly very short trips moving things between those locations.

The Ford dealer wouldn’t repair/replace bad Cat? I thought that they had a 100k warranty on all emission parts Fed mandated.

They probably would, but I prefer to handle everything myself and avoid the dealer whenever possible. This particular truck is currently making over 600HP and the PCM has been flashed over 400 times, so it would also be completely reasonable for them to deny warranty coverage.

 

[markbsae]

Claim the cats under 7/70 federal emissions

 

[Davidwnuc]

Or, it could be this…
https://www.f150gen14.com/forum/threads/p0430-failed-catalytic-converter-pictures.22728/

I would never suggest doing the cat reconditioning drive cycle with a cat that looks like this one. More than one person has lost an engine because of cat failure.

 

[SALEEN961]

Or, it could be this…
https://www.f150gen14.com/forum/threads/p0430-failed-catalytic-converter-pictures.22728/

I would never suggest doing the cat reconditioning drive cycle with a cat that looks like this one. More than one person has lost an engine because of cat failure.

If mine looked anything like that there would be multiple other warning signs like high back pressure, rattling, misfires, high knock retard, bad fuel trim readings, or an unusually high octane adjust ratio. Obviously you would never want to drive a vehicle with a catalyst that was physically broken and coming apart, but I have no reason to suspect a physical failure.

 

[Davidwnuc]

Only code or issue i had was the cat code.
I have the roush supercharger kit but i dont monitor other PIDs so there could have been other signs.
just a cautionary tale.

 

[SALEEN961]

Only code or issue i had was the cat code.
I have the roush supercharger kit but i dont monitor other PIDs so there could have been other signs.
just a cautionary tale.

A physical failure is definitely a good possibility to keep in mind when you get a P0420 or P0430 code, especially on modified vehicles making significantly more power than stock. It's very easy to hit catalyst over-temperature protection at higher power levels, and you can hit at surprisingly low throttle positions if you don't start adding fuel early enough.

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