Electronic Brake Traction Control Module (EBTCM)
WARNING: This page is about a different car, the 2000 Cadillac Catera. However, it is still accessible from the selected car via links, so may be relevant.
EBTCM receives speed signal from left rear Vehicle Speed Sensor (VSS). VSS produces AC signal proportional to speed of axle shaft rotation which is in turn proportional to vehicle speed. EBTCM processes VSS signal and transmits it to ECM.