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Discussion Starter · #1 ·
I have a 2004 Mustang GT that I just recently bought from an auction, took it in to get emissions tested at the dealership and wast told it failed because of a tune the previous owner had on it( Comm. Fail Reason: Cat. Conv. & 02 Unsupported- Programing Error). Asked the dealership to reflash the PCM and they said that they will not due to a recent situation. I have a SCT X4 and was just going to flash a new tune onto the vehicle, but now I am not sure what to do because it would just overlap the previous tune. The only modifications that would require a tune is a BBK cold air intake and a Borla Cat-Back Exhaust. Any suggestions on what to do, can I put a stock PCM in and just upload my custom tune from SCT.
 

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Yea worth a try, but with the current tune as the stock tune, wouldn't the preloaded tune just overlap and not change anything regarding the emissions. On the SCT website it says, "SCT tuning devices will not modify or delete vehicle emissions."
 

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It won’t disable emissions equipment, but since it’s a stockish tune none of those settings will be touched. Those preloaded tunes are pretty similar to stock and should be emissions friendly.

I’d agree with sour. But if the dealer won’t flash it back to stock a preloaded tune is the next best thing since he already has the tuner.
 

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Do you have a OBD2 scanner that will allow you to check monitors? If so, pull up the Monitor readiness and see what is reading incomplete. Is it O2 sensors?

It sounds like the O2 sensors are disabled, which is typically done when cat converters are deleted. Are your cats present?

I also agree with the fact that you do not need a tune for cat-back and CAI. In fact, the hassle you are going through now supports that it's more of a hassle than anything.
 

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From your report, it appears that everything marked unsupported has been turned off in the tune. If they are turned off they will not show up as ready or not ready with a code reader. Are you able to edit the tune to turn them back on?
 

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Does your tuner have preloaded sct tunes or did you get an aftermarket tune? If it has sct tunes on there I don’t see the big deal. They’re glorified factory tunes with all emissions equipment turned on. If that’s the case, try to install the tune. You might need o2 sensor spacers or mil eliminators to pass emissions.
 

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I think everyone is forgetting that his current tune has the o2 sensors turned off which will cause it to fail an inspection. He wants a factory tune but a dealer won’t flash it and he has an x4 that possibly has preloaded tunes which have the emissions equipment turned on. So the easiest way to go about this is to pull the tune as the factory tune to save it, then flash to one of the preloaded tunes.
 
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