I recently bought a Armytrix exhaust for my 2020 Nissan GT-R. The stock exhaust already comes with their own valves. So I went to a shop to change the stock exhaust to the aftermarket exhaust (stock comes with their own valves control). After installing the aftermarket my check engine light is...

I installed a downpipe, y-pipe and full exhaust and the cobb engine and transmission tune and the intake. Before i installed these my car ran perfectly. Now my check engine light is always on. I have to use the cobb to turn it off but then it comes back on every day. Does anyone know what the...