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Hi I just bought from Corsa performance a valve back corsa xtreme exhaust with a x pipe. I have a 2019 C7 Corvette grand sport Auto that came with NPP getting the corsa xtreme exhaust with the X pipe was going to delete the NPP corsa
said that no check engine light was going to pop up, but I got a check engine light so I’m wondering what sensors or resistors do I need in order to get the check engine light to go away?
I got a afm disabler but they did mention my car had 4 valves and the new exhaust system only has 4 so I would prob have to get sensors to replicate it and make the cel not pop up in just not sure what to get
Yes I do think I had the afm valves now that I’m assuming there gone tho I need to get the dummy sensors or the sensors to make the cel not pop up again because now my npp dosent work (which I was aware of when I purchased the exhaust) I just wasn’t expecting the cel now I’m wondering what I should buy what piece
The wide-body cars didn't have AFM valves. You should only have the 2 valves at the muffler outlets.
P26C8 may not have any connection to the exhaust valve failure as it is a general request by the Chassis Control Module to light the CEL due to a DTC being stored in the CCM. The DTCs that are related to the AFM valves are shown in the following picture:
The DTC for the muffler outlet valves is P26C5
Bill
Last edited by Bill Dearborn; May 12, 2026 at 12:41 AM.
Did your exhaust system you had installed remove the AFM valves from the car? After market X pipe? If so then the computer is still looking for those valves regardless if you bought an AFM disabler. Those codes will have to be tuned out. When I went full cat less and aftermarket X pipe on my car that is part of the tuning process. To permanently disable those codes so they will not show up as a CEL.
I’m finding out it did have those afm valves I can’t tune the car due to it would void my aftermarket warranty so next best thing would to purchase those sensors for it so it can act like there still there
Hi I just bought from Corsa performance a valve back corsa xtreme exhaust with a x pipe. I have a 2019 C7 Corvette grand sport Auto that came with NPP getting the corsa xtreme exhaust with the X pipe was going to delete the NPP corsa
said that no check engine light was going to pop up, but I got a check engine light so I’m wondering what sensors or resistors do I need in order to get the check engine light to go away?
We see you're having challenges in clearing this check engine light and would like the opportunity to help the best we can. To get started, please visit: https://s.chevy.com/support-requestand fill out the support request form with all pertinent details. This form helps our team gather the right information and ensures your request is routed appropriately. Your cooperation is much appreciated.
If you haven't already found a solution if you still have the stock exhaust you can just unbolt the valves and plug them back in and zip tie up out of the way. That's what I did.
Finally, GreenVette9 has been there and taken care of the issue. Hope it works for you, too. In any event, why couldn't the vendor or manufacturer of the aftermarket parts tell you this? That's where I've always started with such problems.
What you first need to clarify is what corsa part number did you order? That's absolutely step 1. All these theories and assumptions on this thread do not help you unless we start with the part number you ordered. Also, a photo of exactly what you received would help as well.
And, to say "widebody C7's don't have AFM valves is completely wrong." Exhaust manufacturers have built their C7 offerings based on the following:
All C7 Stingrays have AFM valves
C7 Grand Sports with automatic transmissions have afm valves
C7 Grand Sports with manual transmissions do not have AFM valves.
C7 Z06 & ZR1 do not have AFM valves
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What do I need to remove cel
