AzSideWinder Posted November 12, 2012 Report Share Posted November 12, 2012 I'm driving to my Mustang Club meeting today and my check engine light comes on solid, not flashing. So I stop at the autozone and have them check it out, seems I'm throwing a code P0420. Catalyst System Efficiency Below Threshold (Bank 1) I have a 2012 Shelby GT500 with about 5500 miles on it. The only mods I've done to this is a VMP tune a smaller pulley and a JLT CAI. I reset the codes and haven't had a chance to drive it again since the reset. What I'm wanting to know is has anyone else ever had this happen? I'm also concerned I have a bad cat that could have been caused by the tune. If I take it to the dealership for warranty work Ill probably have to return everything to stock except for the CAI????? Can anyone shed some light on this and what you recommend? The Shelby seems to be running just fine, Ill find out tomorrow if it comes back on again. I've been told to reset it and take it for a long drive, that i might have gotten some bad gas. Link to comment Share on other sites More sharing options...
Grabber Posted November 12, 2012 Report Share Posted November 12, 2012 If you take it back to the dealer to trouble shoot a code that could be caused my your mods...it is not Fords fault. I would contact your tuner and tell him what is going on and get some advice from him. If you take the car to the dealer to trouble shoot a code, you will need to return the car to 100% stock. If you return it to stock and drive it for a week and the code does not come back, then you will know that the code has been caused by your mods. Link to comment Share on other sites More sharing options...
Grabber Posted November 12, 2012 Report Share Posted November 12, 2012 Send Barry a e-mail and he will help you. bj@vmptuning.com Link to comment Share on other sites More sharing options...
AzSideWinder Posted November 12, 2012 Author Report Share Posted November 12, 2012 Well the tunes been on the car for about 1000 miles. Im aware of Ford looking to get out of the warranty for any reason. Ill have to contact Barry, I'm hoping someone else has been through this. Link to comment Share on other sites More sharing options...
Grabber Posted November 12, 2012 Report Share Posted November 12, 2012 Well the tunes been on the car for about 1000 miles. Im aware of Ford looking to get out of the warranty for any reason. Ill have to contact Barry, I'm hoping someone else has been through this. Google your problem. I see many posts on this over at SVT performance come up when you google it. Link to comment Share on other sites More sharing options...
Madlock Posted November 12, 2012 Report Share Posted November 12, 2012 I'd restore the tune to stock and take it in for warranty service. It may run a little iffy, but if the prpblem's a cat-related code; that's what they're likely to focus upon which should be all that matters if you have a bad cat or sensor. Link to comment Share on other sites More sharing options...
AzSideWinder Posted November 12, 2012 Author Report Share Posted November 12, 2012 I'd restore the tune to stock and take it in for warranty service. It may run a little iffy, but if the prpblem's a cat-related code; that's what they're likely to focus upon which should be all that matters if you have a bad cat or sensor. Think they'll notice the pulley being smaller? It looks like the original just smaller. Even if I flash back the stock tune wont they be able to see that in the computer? Link to comment Share on other sites More sharing options...
Grabber Posted November 12, 2012 Report Share Posted November 12, 2012 They may plug into your computer and re flash it with the latest update that they have. Then your tune will be lost. The best thing to do is to be honest with them or flash it back to stock. As for the pulley, if you are flashed back to stock, you can drive it, but do not get it into boost. If they take it for a test drive and get it into boost with the small pulley and the stock tune...more codes could be thrown and or it will not run right and they will be wondering what is wrong with the car. Link to comment Share on other sites More sharing options...
Madlock Posted November 12, 2012 Report Share Posted November 12, 2012 Iffy. Really depends upon the tech. If you walk in leading them in the direction of the cat, hopefully they won't pay much attention to the engine compartment. Otherwise, this is just the kind of risk you're always going to run without returning the car to stock. And though a real richard of a tech would note the car'd service history, unless they can prove a problem is a direct result of modifications you've made, Ford remains obligated to repair the car under warranty. Link to comment Share on other sites More sharing options...
Grabber Posted November 12, 2012 Report Share Posted November 12, 2012 Iffy. Really depends upon the tech. If you walk in leading them in the direction of the cat, hopefully they won't pay much attention to the engine compartment. Otherwise, this is just the kind of risk you're always going to run without returning the car to stock. And though a real richard of a tech would note the car'd service history, unless they can prove a problem is a direct result of modifications you've made, Ford remains obligated to repair the car under warranty. You will need to hire a attorney to make them do that. That is going to cost a chunk of change. Link to comment Share on other sites More sharing options...
Grabber Posted November 12, 2012 Report Share Posted November 12, 2012 I guess you could go to arbitration. Link to comment Share on other sites More sharing options...
AzSideWinder Posted November 12, 2012 Author Report Share Posted November 12, 2012 Arbitration? Seriously Ill know whats wrong completely before any dealership looks at this car. This is the best tech info this site could muster huh? Never mind guys I bought a 60k car a cat wont break me. Link to comment Share on other sites More sharing options...
05mustangman Posted November 12, 2012 Report Share Posted November 12, 2012 Gotta give it little time Joe. Since it is a cat below efficiency code, I would start by checking out the cat to make sure its not plugged. With that code, the most common problem that I've read about has been a possible plugged cat. But you also might want to see what caused the cat to get plugged if that is the case. Link to comment Share on other sites More sharing options...
Firekiller Posted November 12, 2012 Report Share Posted November 12, 2012 I had the exact same problem pop up on me the last day at the Ford Nationals in Carlisle this past year. I just reset the code and it drove fine, but would come on periodically. I have many mods so going back to stock for me was not an option, so I took it to my local ford dealer and told them what was wrong and how much it will cost me. Now mind you I have done a lot of business with them, but they said no problem that they will replace it under warranty. The tech also stated that there has been an abundance of cats going out on these cars. He did not say whether it was due to mods or manufacturing, but he has done at least 2 dozen in the last year (all models). If you have a good relationship with the service dept. I would just be honest with them and maybe they will replace it under warranty. If you go in and try to hide the mods they may not be so nice and charge you. Just my 2 cents. Keep us posted on how it works out. Link to comment Share on other sites More sharing options...
AzSideWinder Posted November 13, 2012 Author Report Share Posted November 13, 2012 I had the exact same problem pop up on me the last day at the Ford Nationals in Carlisle this past year. I just reset the code and it drove fine, but would come on periodically. I have many mods so going back to stock for me was not an option, so I took it to my local ford dealer and told them what was wrong and how much it will cost me. Now mind you I have done a lot of business with them, but they said no problem that they will replace it under warranty. The tech also stated that there has been an abundance of cats going out on these cars. He did not say whether it was due to mods or manufacturing, but he has done at least 2 dozen in the last year (all models). If you have a good relationship with the service dept. I would I just be honest with them and maybe they will replace it under warranty. If you go in and try to hide the mods they may not be so nice and charge you. Just my 2 cents. Keep us posted on how it works out. So did it turn out to be a CAT? If yes do they have any idea what may have caused it? I have a good relationship with my Lincoln Ford dealer. I'm just wondering if they consider a pulley and tune a drastic mod. Link to comment Share on other sites More sharing options...
Firekiller Posted November 13, 2012 Report Share Posted November 13, 2012 Yes it was a bad passenger side cat. Whether or not they would consider it a drastic mod or not I couldnt say, but if you have a tech that you are friendly with I would get his opinion before going to someone in a higher position to try to feel them out. The tech may be able to lead you in the right direction on whether or not to return to stock. My car would be considered by most to be drastically modded, I am running the Kenne Bell S/C and putting out just over 800 hp. with all the suppporting mods to go with it. Link to comment Share on other sites More sharing options...
AzSideWinder Posted November 14, 2012 Author Report Share Posted November 14, 2012 For future reference for this site. Description This DTC sets when the bank 1 catalyst system efficiency is below the acceptable threshold. Possible Causes Use of leaded fuel Damaged heated oxygen sensor (HO2S) Out of range engine coolant temperature (ECT) sensor High fuel pressure Damaged exhaust manifold Damaged catalytic converter Oil contamination Cylinder misfiring Downstream HO2S wires incorrectly connected Damaged exhaust system pipe Damaged muffler/tailpipe assembly Retarded spark timing Leaking fuel injector Diagnostic Aids Under normal closed loop fuel conditions, high efficiency catalysts have oxygen storage which reduces the frequency and amplitude of the downstream HO2S as compared with an upstream HO2S signal. As catalyst efficiency deteriorates, its ability to store oxygen declines and the downstream HO2S signal has an increased amplitude and frequency, approaching the amplitude and frequency of the upstream HO2S. For vehicles with universal HO2S, the PCM compares the signal line length of the downstream HO2S to an expected signal line length of the downstream HO2S with a deteriorated catalytic converter. For all others, the signal line lengths of the downstream HO2S are compared against the signal line lengths of the upstream HO2S. Link to comment Share on other sites More sharing options...
05mustangman Posted November 15, 2012 Report Share Posted November 15, 2012 Joe were you able to find out what caused your code yet? Link to comment Share on other sites More sharing options...
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