Check engine light

Hey all, so I just had my dreaded check light come on. On Friday night I picked it up from the local performance shop with Kooks LT headers Corsa Xtreme exhaust. Does anybody have any idea what caused it? my Mustang has just shy of 10K miles?

Did you have her tuned for the long tubes ? .. it's probably the cats .

Jprada1210 said:

Did you have her tuned for the long tubes ? .. it's probably the cats .

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Yep sure did, got the SCT tuner.

Read the code and tell us what it is!

Dominant1 said:

Read the code and tell us what it is!

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Will do in the AM. Got tomorrow off to try and get this solved.

Use the SCT device to pull the code. Who's your tuner?

Kahboom said:

Use the SCT device to pull the code. Who's your tuner?

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Will do.

The tune is what was pre-loaded on the SCT.

Dominant1 said:

Read the code and tell us what it is!

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I re-ran/installed the tune so it cleared the codes, but they were P0420 & P0430

kanga80 said:

Will do.

The tune is what was pre-loaded on the SCT.

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Get an email tune from a vendor specific for the headers. Pre-loaded isn't going to work.

Chameleon said:

Get an email tune from a vendor specific for the headers. Pre-loaded isn't going to work.

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Ok, will do, did a quick search and will go with Lund.

Those are codes for the rear o2's. You will need to have them turned off along with COT. Hopefully you don't have emission testing.

OP, in case you didn't know, tuning the rear O2s off will cause an emissions inspection failure in NC as they test via the OBD port. Just wanted to give you a heads up to be prepared, in case you didn't already know.

Dragster said:

OP, in case you didn't know, tuning the rear O2s off will cause an emissions inspection failure in NC as they test via the OBD port. Just wanted to give you a heads up to be prepared, in case you didn't already know.

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Thanks. Just talked to my tuner and he is going to give me an "emissions ready" tune with the O2 sensor on and a "regular tune" with the sensor off.

kanga80 said:

Thanks. Just talked to my tuner and he is going to give me an "emissions ready" tune with the O2 sensor on and a "regular tune" with the sensor off.

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Exactly what I have. Never had any issues passing. Most places don't bother doing a visual inspection!

WestCyril said:

Exactly what I have. Never had any issues passing. Most places don't bother doing a visual inspection!

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Awesome, I spent all day on the internet worrying my ass off that I was screwed. Then stumbled across a thread saying that an emissions tune will fix it. So I PM'd the poster and he had his car registered in same state, had same errors, same headers, AND same tuner. His issue hasn't re-surfaced since he got the 2 tunes. Extremely relieved now.