Circuit Description
WARNING: This page is about a different car, the 2004 Cadillac SRX. However, it is still accessible from the selected car via links, so may be relevant.
The electronic brake control module (EBCM) sends an engine drag control (EDC) request via a dedicated data line. The engine control module (ECM) supplies a pull up voltage of 12 volts that the EBCM switches to ground to create the signal.