GS300 makes weird actuator noise when braking

[azguy0801]

New rotors, new pads, fluids topped off, but a weird actuator noise (comes on during braking) and (only when the brake pedal is applied) sometime at idle, I Isolated the noise around the brake booster, trying to figure out the Aluminum canister next to the brake booster, and cant seem to track down the name......I'm guessing maybe there's air in the ABS module, and I may have to bleed the system? But the noise can be heard inside the interior and outside the vehicle....need help

[2JayZ]

The noise you hear is the ABS pump. Considering the work you just did this likely means you have either air in the system and/or the incorrect fluid level in the master cylinder reservoir. Recommend you bleed the brakes and when done be certain your fluid level is below the MAX line.

[mizike29]

I just bought a used 2002 lexus GS300 with 63k miles on it, when I pull in to a parking spot, pretty soft brake, slow brake and turning a bit, my brake pedal vibrates and the buzzing noise comes on.  Only seems to do it on slow stops when turning left or right.  My mechanic has said all 4 ABS have error codes so he is changing those, hopefully nothing else major.