GM Service Manual Online
For 1990-2009 cars only

The EBCM performs one initialization test each ignition cycle. The initialization of the EBCM occurs when one of the following conditions occur:

    • Both of the following conditions occur:
       - The EBCM receives that there is a minimum of 500 rpm from the PCM via class 2 serial data message.
       - The stoplamp switch is not applied.
    • Both of the following conditions occur:
       - The vehicle speed is greater than 16 km/h (10 mph).
       - The stoplamp switch is applied.

The initialization sequence cycles each solenoid valve and the pump motor (as well as the necessary relays) for approximately 1.5 seconds 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 system operation.