Brake warning light and loud buzzer?

Has anyone had this warning and know why it happens?

i was slowly backing out of a parking spot, riding the brake pedal slightly so as to not back into cars behind me, when this annoying loud buzzer went off and the BRAKE light was on. The car would drive but i couldn't take it, had to pull over and stop, then restarted but got a dash full of lights and no ready, tried again and all was good.

i've been keeping the float charger on the 12V aux battery and it is less than 2 years old, so i suspect something else, but i will double check that it is good. Never had this fault occur before, so wondering what was the cause.

Is it the low brake vacuum warning buzzer you're hearing ?

Turn the car on to ready and rapidly pump the brake pedal through its full stroke a few times as quick as you can and you should trigger the warning light and buzzer for the brakes due to low vacuum, however it should recover after a few seconds.

If it's the same warning you were seeing then I'd say there could be something wrong with the vacuum in the brake system. As there have been a couple of recalls for the vacuum pump now it could be your issue...

One issue I've seen reported is dirt clogging up the output of the vacuum pump so if you can find the outlet try cleaning it.

Dirt clogging is pretty common due to the poor location of the pump, but they also rot out for the same reason. Mine's been replaced twice and I don't really understand why they didn't put it under the hood