Abs off, but brakes now giving tones intermittent

Abs system is proactively being ignored, as of 8 months ago. Car has been driven and brakes pass inspection 11/25.

Brake alarm tone interintermittently comes on for short minute, and brakes are less responsive, as if power brakes are not being powered. Brakes work, but not as responsive as they should be. That is our main concern. It it a particular sensor, which?

160k miles near Philadelphia pa

Sometimes when started, and brakes are very hard to push, not braking correctly. Abs has been not working for over 6 months, but this is a new issue.

What sensor is causing this and can it be replaced.


Also, possibly not related, but for fyi. Also, when you get into car, the same tone starts. As well as when you exit car, the tone sounds

 

Anyone have any ideas that may help? we have been trying to get an appointment at a trusted machanic, but it is a busy time of year. i was hoping i could tell him something more than what i have so far.