Kickback & Pump Motor
WARNING: This page is about a different car, the 1999 Acura 3.0CL and 1999 Acura 2.3CL. However, it is still accessible from the selected car via links, so may be relevant.
The pump motor operates when ABS is functioning, and fluid in reservoir is forced out to master cylinder causing kickback at brake pedal. ABS control unit checks pump motor operation during initial diagnosis and vehicle starts. A faint noise may be heard under these conditions and also when ABS is active. This is a normal condition.