Catalytic converter

[Jimmy SHO]

Hi everyone I have a 2016 Ford Taurus Sho with a magnaflow exhaust when I bought the car it was straight piped from the resinator back to the rear mufflers, I've had the car for 4-5 months and it has always had a P0420 and P0430 code, so i replaced the exhaust with the magnaflow first, the car runs good with good gas mileage but I don't know what to do to get rid of the cat code ??? Ford cats are so expensive I want to see if anyone has any better options first. Thanks
Also how many cats do I need if I go the replace catayltic converter route.

 

[dillonschmadeke]

Well, you could always go with high flow catted downpipes from PPE or SW and get a tune for them and make some more power. But if you are wanting to stay stock there are cats you can buy on eBay for cheap, not sure on the quality but I'm sure you get what you pay for. There is 02 spacers you can use to possibly get rid of the code but, that is just masking the problem.

 

[kryptto]

I sold my spacers and never used them.. the person I sold them to I don't recall. the statement you make, straight pipe after the resonator back should not create those codes unless you are describing the layout wrong. I am ppe straight pipes and eliminated the cats, then cut the 3rd cat which is not monitored which runs into the resonator after the O2s. all gone on my car. the O2's are in the straight PPE pipes but eliminated with a tune by silencing the alarm. I am concerned your codes are possibly clogged cats. so can it be a PVC oil collection issue running into the cats and fouling them, too much octane booster, someone ran a cat cleaner that clogged them up?

another observation.... you might be catless already. check your spark plugs and make sure they are gapped correctly and NOT too gapped. lastly a little O2 cleaner on the sensors POST exhaust could clear fouling.

in my experience there are many either post resonator or post 3rd cat back kits that won't cause the p0420 or 30 errors. magna flow which I have their mufflers has a resonator swap cat back kit.

 

[Jimmy SHO]

I sold my spacers and never used them.. the person I sold them to I don't recall. the statement you make, straight pipe after the resonator back should not create those codes unless you are describing the layout wrong. I am ppe straight pipes and eliminated the cats, then cut the 3rd cat which is not monitored which runs into the resonator after the O2s. all gone on my car. the O2's are in the straight PPE pipes but eliminated with a tune by silencing the alarm. I am concerned your codes are possibly clogged cats. so can it be a PVC oil collection issue running into the cats and fouling them, too much octane booster, someone ran a cat cleaner that clogged them up?

another observation.... you might be catless already. check your spark plugs and make sure they are gapped correctly and NOT too gapped. lastly a little O2 cleaner on the sensors POST exhaust could clear fouling.

in my experience there are many either post resonator or post 3rd cat back kits that won't cause the p0420 or 30 errors. magna flow which I have their mufflers has a resonator swap cat back kit.

Ok what tune did you you use to tune them out???
I'm pretty sure there not clogged cause the car still runs normal, I had a mechanic check and the cats are there, I did put brand new spark plugs I left them with the factory soark plug gap and pvc plug or whatever those things are called can't remember. I have a magnaflow exhaust system on there and the codes are still there.

Is there a chance It could be bad o2 sensors???
Thanks for the help !!!

 

[kryptto]

answer your question on the tune: I use a custom calibration from AJP Turbo (you can also look Unleashed) specifically to handle the PPE straight pipes contact AJP. These tuners can "silence" the rear O2 monitor logic so the light stays off. Fair warning: This will usually keep your Emissions Readiness monitors in a not ready state, so if you live in a state with OBDII plug-in inspections, you won't pass without functional cats.
Regarding your situation: the fact that you have both P0420 and P0430 makes O2 sensors highly unlikely. It’s rare for two sensors to fail simultaneously. It almost always points to an upstream issue affecting both banks or chemical failure of the cats themselves.
1. TSBs
Ford has released several bulletins for the 3.5L EcoBoost regarding catalyst efficiency. You should mention these to your mechanic:
TSB 14-0102: Specifically for 2013-2014 Taurus/Explorer. It acknowledges that these codes can trigger and mandates replacing the affected catalyst and performing a PCM software update. Even if you are a 2016, the software logic update is often the fix.
TSB 14-0017 / 13-8-1: These deal with the "Intercooler Moisture" issue. If your car ever stumbles under hard acceleration in humid weather, it's sending slugs of water/unburnt fuel into the cats. This kills the chemical substrate.
SSM 44521: Deals with oil consumption from the PCV system (that "PVC" thing you mentioned). If the valve cover/separator is faulty, oil enters the combustion chamber and "poisons" the catalyst, making it look dead to the computer even if it isn't clogged.
2. The Cat Count
If you go the replacement route, you have three total, but only two matter for the codes:
Primary Cats (qty 2): These are integrated into the downpipes directly off the turbos. These are the only ones the computer monitors.
Secondary Cat (qty 1): This is in the mid-pipe before the resonator. It is unmonitored. You can delete this one without ever seeing a light.
3. Tests
Since the car runs normal, the cats aren't physically melted/blocked yet. They are just chemically inefficient.
Temperature Test then have your mechanic use an IR thermometer. The exit of the cat should be roughly 100°F hotter than the inlet. If they are the same temp, the cat isn't "lighting off."
Spark Plug Gap: You mentioned factory gap double check that. For the SHO, we usually recommend .028". If you are at .033" or higher, you risk micro-misfires that dump raw fuel into the cats killing them.
Don't just throw parts at it yet. Check that PCV valve and the intercooler for "gunk" first. If the engine is dirty, it'll just **** the new cats you buy too.

Last thought, did the car get tuned and leave you with the problems of the light on?

 

[Jimmy SHO]

answer your question on the tune: I use a custom calibration from AJP Turbo (you can also look Unleashed) specifically to handle the PPE straight pipes contact AJP. These tuners can "silence" the rear O2 monitor logic so the light stays off. Fair warning: This will usually keep your Emissions Readiness monitors in a not ready state, so if you live in a state with OBDII plug-in inspections, you won't pass without functional cats.
Regarding your situation: the fact that you have both P0420 and P0430 makes O2 sensors highly unlikely. It’s rare for two sensors to fail simultaneously. It almost always points to an upstream issue affecting both banks or chemical failure of the cats themselves.
1. TSBs
Ford has released several bulletins for the 3.5L EcoBoost regarding catalyst efficiency. You should mention these to your mechanic:
TSB 14-0102: Specifically for 2013-2014 Taurus/Explorer. It acknowledges that these codes can trigger and mandates replacing the affected catalyst and performing a PCM software update. Even if you are a 2016, the software logic update is often the fix.
TSB 14-0017 / 13-8-1: These deal with the "Intercooler Moisture" issue. If your car ever stumbles under hard acceleration in humid weather, it's sending slugs of water/unburnt fuel into the cats. This kills the chemical substrate.
SSM 44521: Deals with oil consumption from the PCV system (that "PVC" thing you mentioned). If the valve cover/separator is faulty, oil enters the combustion chamber and "poisons" the catalyst, making it look dead to the computer even if it isn't clogged.
2. The Cat Count
If you go the replacement route, you have three total, but only two matter for the codes:
Primary Cats (qty 2): These are integrated into the downpipes directly off the turbos. These are the only ones the computer monitors.
Secondary Cat (qty 1): This is in the mid-pipe before the resonator. It is unmonitored. You can delete this one without ever seeing a light.
3. Tests
Since the car runs normal, the cats aren't physically melted/blocked yet. They are just chemically inefficient.
Temperature Test then have your mechanic use an IR thermometer. The exit of the cat should be roughly 100°F hotter than the inlet. If they are the same temp, the cat isn't "lighting off."
Spark Plug Gap: You mentioned factory gap double check that. For the SHO, we usually recommend .028". If you are at .033" or higher, you risk micro-misfires that dump raw fuel into the cats killing them.
Don't just throw parts at it yet. Check that PCV valve and the intercooler for "gunk" first. If the engine is dirty, it'll just **** the new cats you buy too.

Last thought, did the car get tuned and leave you with the problems of the light on?

Thanks for the information!!! Thats helps out so much thank you !!!! I'm not sure if the car got tuned I bought it in August of 2025 with 109k miles on it, and the check engine light has been on ever since.

 

[G Kitsmiller]

I had an exhaust shop tell me my codes are caused by clogged cats and blown turbos. I used Cataclean and put on a UPR oil catch can. Problem solved. Turbos are designed to spit oil under pressure. I had to teach that to men at an exhaust shop. SMH. (Blonde Girl)