Borla exhaust problem.
Thread Starter
1st Gear
Joined: Jul 2025
Posts: 1
Likes: 0
Borla exhaust problem.
My 2020 C8 has a Borla cat back exhaust. It is causing recurring, steady “ Check engine” lights. The local Chevy dealer checks and resets the light but cannot explain what is causing the problem. Any ideas?
Melting Slicks
Joined: Apr 2021
Posts: 2,759
Likes: 2,328
From: Simi Valley, CA
2022 C8 of the Year Finalist - Modified
They should start by checking that the AFM and NPP valves open and close when they should. Next, they should do a relearn of the exhaust system, which is a procedure they can do with their computer.
HOWEVER, if the dealer doesn't already know these steps (same as they would do for the OEM NPP performance exhaust on a C8), then maybe you should start by taking it to a dealer whose technicians know what they are doing.
If the do find a problem with exhaust valves that can't be solved with the relearn procedure, contact Borla before paying for any work to be done. Their product warranty is 1 million miles and their customer service is excellent.
HOWEVER, if the dealer doesn't already know these steps (same as they would do for the OEM NPP performance exhaust on a C8), then maybe you should start by taking it to a dealer whose technicians know what they are doing.
If the do find a problem with exhaust valves that can't be solved with the relearn procedure, contact Borla before paying for any work to be done. Their product warranty is 1 million miles and their customer service is excellent.
Supporting Vendor
Joined: Nov 2015
Posts: 1,263
Likes: 280
From: Orange County, NY
They should start by checking that the AFM and NPP valves open and close when they should. Next, they should do a relearn of the exhaust system, which is a procedure they can do with their computer.
HOWEVER, if the dealer doesn't already know these steps (same as they would do for the OEM NPP performance exhaust on a C8), then maybe you should start by taking it to a dealer whose technicians know what they are doing.
If the do find a problem with exhaust valves that can't be solved with the relearn procedure, contact Borla before paying for any work to be done. Their product warranty is 1 million miles and their customer service is excellent.
HOWEVER, if the dealer doesn't already know these steps (same as they would do for the OEM NPP performance exhaust on a C8), then maybe you should start by taking it to a dealer whose technicians know what they are doing.
If the do find a problem with exhaust valves that can't be solved with the relearn procedure, contact Borla before paying for any work to be done. Their product warranty is 1 million miles and their customer service is excellent.
https://www.borla.com/support/million-mile-warranty
Let me point out detail pertaining to their valved exhausts (aka valved Borla catbacks for C8):
"BORLA® will warranty black coatings, tip finishes, carbon fiber and moving parts including but not limited to valves and actuators for one year. This does not include blemishes or marring of appearance due to weather, road hazards, lack of maintenance or extremes of heat or cold. This warranty shall apply only if BORLA's examination of the returned product discloses a manufacturing or material defect, and BORLA's sole obligation under this warranty shall be limited to repair or replacement at BORLA's option."
With that said OP feel free to call or text me if you need any help troubleshooting your catback 201-575-0861.
Thank you,
Ciro
Racer
Joined: Nov 2014
Posts: 326
Likes: 31
From: Williamsburg VA
Needs a relearn for AFM and NPP valves. Either find a new dealer, local buddy with a scan tool, or get one off Amazon +or-$150 and do it yourself-you can do it easy or if needed I wrote the steps down.
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From: GA
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3rd Gear
Joined: Aug 2024
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I have a similar problem. Car throws a P12F0 code and have had it at my local dealer a couple of times. The problem is related to the AFM valves being blown open, I assume, due to back pressure in the exhaust. GM has documentation and sent to dealers telling them to look out for this situation and the Borla exhausts. I purchased my 2023 last year (I year old) and already had the exhaust on it. I contacted Borla and since I’m not the original owner, they are willing to sell me a fix at a reduced cost. Not sure if this would solve my problem or not. That’s my story, so perhaps the original thread owner’s issue is similar. I’ve been testing various hypothesis. If you drive in Z-mode or manual mode, the car doesn’t go into 4 cylinder mode so doesn’t throw a code. If I drive it in one of these modes until the engine reaches operating temperature, I can then put back into the other modes and car doesn’t throw the code. As long as the car is at operating temp, no codes. That’s all I know at this point.