Antilock Braking Mode

The purpose of the Antilock Brake System (ABS) is to maintain vehicle maneuverability under severe braking conditions on most road surfaces.

The ABS/TCS system monitors the speed of each wheel during a braking maneuver.

The Electronic Brake (and Traction) Control Module (EBCM/EBTCM) processes these values in order to produce command controls. These command controls prevent the braked wheels from slipping.

The BPMV regulates brake fluid pressure based on road conditions as interpreted by the EBCM/EBTCM, regardless of the master cylinder output pressure.

The BPMV can maintain or adjust the brake fluid pressure to the brake calipers under ABS conditions. The BPMV cannot increase the pressure above the level of pressure applied from the master cylinder.

However, during TCS operations, the modulator can apply pressure to the front brake calipers if the EBCM/EBTCM requires that a wheel be slowed or regulated.

SYSTEM SELF TEST
The EBCM/EBTCM performs an automatic test when the ignition is turned to RUN. This test occurs one time for each ignition cycle.

The self test cycles the following components in order to check component operation:
^ The valve solenoids
^ The pump motor and the necessary relays

If any malfunction is detected, the EBCM/EBTCM will set a Diagnostic Trouble Code (DTC).

The self test may be heard and felt while it is taking place. The self test is a normal mode of operation.