I had to find on some strange forum the CEL codes to monitor my DPF. Otherwise I would never know when it is filling up and never be able to reach out a highway

I had to find on some strange forum the CEL codes to monitor my DPF. Otherwise I would never know when it is filling up and never be able to reach out a highway to allow it to clean nicely. This shouldn't be obscure. But they keep saying "hey this is our intellectual property"