Lumina V6-204 3.4L DOHC VIN X SFI (1996)
Electronic Brake Control Module: Description and Operation
DESCRIPTION
The ABS system is controlled by a microprocessor based Electronic Brake Control Module (EBCM). Inputs to the system include four wheel
speed sensors, brakes, ignition switch and unswitched battery voltage. Outputs include three bi-directional motor controls, three lamp controls, two
solenoid controls and the system enable relay. A serial data line, located in terminal 9 of the Data Link Connector (DLC), is provided for service
diagnostic tools and assembly plant testing.
The EBCM monitors the speed of each wheel. If any wheel begins to approach lock-up and the brake switch is on, the EBCM controls the motors
and solenoids to reduce brake pressure to the wheel approaching lock-up. Once the wheel regains traction, brake pressure is increased until wheel
begins to approach lock-up. This cycle repeats until either vehicle comes to a stop, the brake is released or no wheels approach lock-up.
Additionally, the EBCM monitors itself, each input and each output for proper operation. If any system fault is detected, the EBCM will store a
DTC in nonvolatile memory.
On a EBTCM, the ABS portion of the module operates the same as a EBCM. A EBTCM is used if the vehicle is equipped with either the
Enhanced Traction System (ETS) or Traction Control System (TCS). The ETS or TCS portion of the EBTCM monitors wheel spin slip through
the drive wheels speed sensors. If the wheels begin to slip, the EBTCM determines the desired wheel torque needed to minimize wheel slip. This
information is sent to the PCM through the Serial data link. On models equipped w/ETS, the PCM controls engine torque by ignition retard and
transmission shifts. On models equipped w/TCS, the PCM controls engine torque by ignition retard, transmission shifts and applies brakes several
times until the vehicle regains traction. Once the vehicle regains traction, brake pressure is decreased and engine torque reduction is no longer
requested. This cycle repeats until traction control is no longer necessary.
