Don't know the answer to your question, but I had exactly the same problem
few months ago. It came back on its own. I noticed I now need to slightly
hold the brake a little longer for it to kick in. It seems it has some type
of intelligence of its own. Resetting the computer might fix the problem.
Thought about it but never tried it.

Hard brake might affect how it behaves. So I try to avoid hard brake. On the
other hand avoiding accident is probably more important than this, :).