For 1990-2009 cars

The EBCM performs the Initialization test once each ignition cycle when the vehicle speed reaches 6 Km/h (4 mph) and the EBCM does not see a brake switch input. If the EBCM sees a brake switch input, the initialization test runs when the vehicle speed reaches 15 Km/h (9 mph) . The Initialization sequence cycles each valve solenoid and the pump motor (as well as the necessary relays) to check component operation. If any error is detected, the EBCM will set a DTC. The Initialization sequence may be heard and felt while it is taking place, and is considered part of normal operation.