System Self-Test
WARNING: This page is about a different car, the 1997 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.
The EBTCM performs an automatic test once every ignition cycle when ignition is turned to RUN position. The self-test cycles each solenoid valve and pump motor (and any necessary relays) in order to check component operation. If a malfunction is detected, EBTCM will set a DTC. The self-test may be heard or felt, and is a normal mode of operation.