LT Header + HFC = P0420 code.

[Joe 5.0]

After a couple hundred miles with my Longtube headers and high flow cats, my check engine light popped up. I checked the code with my handheld tuner and it reads, "P0420."

I cleared the code and drove around about 5 miles, and the check engine light hasn't popped back up, but I have a feeling it will according to other people having the same issue.

Does anyone else have this problem?

My questions to you guys are:

1. I have cleared the code for now, but is it safe to drive the car with this code?

2. Is there anyway to fix this code so I don't have any problems with my New York annual inspection?

Thanks in advance for all of your help.

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[2015 Silver GT]

Yes it is safe to drive the car but you will need to have the rear o2's turned off in the tune because of the high flow cats. Because you are in NY that's going to be a problem come emission time.

Also make sure your tuner turned off COT.

 

[Joe 5.0]

Bump. Could use some more opinions and thoughts...

 

[2015 Silver GT]

No need to bump, I gave you the correct info already. How you want to address it is up to you. P0420 is simply a cat efficiency code caused by your high flow cats. Resetting the code means you have to go through all the Ford readiness drive cycles and trust me that won't be easy to get the car ready for emission testing.

 

[Zemedici]

No need to bump, I gave you the correct info already. How you want to address it is up to you. P0420 is simply a cat efficiency code caused by your high flow cats. Resetting the code means you have to go through all the Ford readiness drive cycles and trust me that won't be easy to get the car ready for emission testing.

this.

There's a reason HFC are cheaper than OEM cats as well, they normally don't perform up to the same standards. However, is the car tuned?

 

[gsxr1300]

You can try adding these.
http://vibrantperformance.com/catalo...oducts_id=1605

 

[Joe 5.0]

Thanks all for your help.

I was thinking of getting the Vibrant Performance kit. The kit would install on my rear o2 sensor which is located after the cat? I have heard of many good reports from the fouler trick.

First, since I cleared the code via my SCT tuner, is the drive cycle a must? My inspection isn't until early next year, so there is plenty of time to drive around on the highway and put some miles on the car.

Second, is there any way my tuner can make an emissions tune which makes the sensors and all monitors read, "ready" to avoid the drive cycle. This tune would obviously be uploaded before the inspection. I have heard this is possible...

I'm frustrated :headbonk:

 

[stage3s4]

Thanks all for your help.

I was thinking of getting the Vibrant Performance kit. The kit would install on my rear o2 sensor which is located after the cat? I have heard of many good reports from the fouler trick.

First, since I cleared the code via my SCT tuner, is the drive cycle a must? My inspection isn't until early next year, so there is plenty of time to drive around on the highway and put some miles on the car.

Second, is there any way my tuner can make an emissions tune which makes the sensors and all monitors read, "ready" to avoid the drive cycle. This tune would obviously be uploaded before the inspection. I have heard this is possible...

I'm frustrated :headbonk:

there should be way to do this in the tune. Its done on many cars.

 

[2015 Silver GT]

there should be way to do this in the tune. Its done on many cars.

There is but it's highly illegal and something most tuners are not willing to do.

 

[stage3s4]

There is but it's highly illegal aand something most tuners are not willing to do.

Not true. In places like Michigan and Florida there is not state inspection. They can do whatever they want. Also some people may want to use for other reasons than passing an inspection.

 

[2015 Silver GT]

Not true. In places like Michigan and Florida there is not state inspection. They can do whatever they want.

Yea you keep thinking that........

Regardless the OP is in NY.

 

[stage3s4]

Yea you keep thinking that........

Regardless the OP is in NY.

ok man. I been doing it for about 10 years. I have no idea what I'm talking about

 

[PonyGrrrl]

Yea you keep thinking that........



Regardless the OP is in NY.

Florida hasn't had inspections since Bush was our governor.


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[Cloak]

You can try adding these.
http://vibrantperformance.com/catalo...oducts_id=1605

have you tried this yet? I would like to find a way to keep the o2 sensors on and run off-road headers and still pass emissions

 

[astolt12]

have you tried this yet? I would like to find a way to keep the o2 sensors on and run off-road headers and still pass emissions

I used this on my old mustang except i made them out of spark plug anti fouler spacers. I think the hole is 14mm (i may be wrong).

all it does it trick the O2 sensors into thinking there is more air and it wont throw a deficiency code.

Best thing you can do is get your tuner to turn off your 02 sensors. If you have to pass emissions it'll do it, but you have to take the tune off and let the ECM reset. Drive it like a grandma for a little and then get it inspected.

With my old one i passed doing exactly that.

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