General Troubleshooting Information: Kickback
WARNING: This page is about a different car, the 2009 Honda S2000, 2008 Honda S2000, 2007 Honda S2000, and 2006 Honda S2000. However, it is still accessible from the selected car via links, so may be relevant.
The pump motor operates when the VSA modulator-control unit is functioning, and the fluid in the reservoir is forced out to the master cylinder, causing kickback at the brake pedal.