Again agreeing with Jack; it's true that much of Kant's argument about the CI is based on consequences. Conceptually, however, the CI and its association with objective morality do require it to be purely non-consequence-based. If it were consequence based, then if the consequences were different, it wouldn't necessarily hold, so it would not be "categorical."

I agree that, fundamentally, any intelligible concept of ethics will rest on consequences. But the idea behind the CI is that it is a priori, which is why it's such a terrible and convoluted idea.