Skylark L4-144 2.4L DOHC VIN T SFI (1997)
Electronic Brake Control Module: Description and Operation
DESCRIPTION
The controlling element of ABS VI is a microprocessor based Electronic Brake Control Module (EBCM). Inputs to the system include four wheel
speed sensors, the brake switch, the brake fluid level switch, ignition switch, and unswitched battery voltage. Outputs include three bi-directional
motor controls, two solenoid controls and the Electronic Brake Control Relay. A serial data line is used for service diagnostic tools (Scan Tool),
assembly plant testing and control of indicator lamps in the IPC.
OPERATION
The EBCM monitors the speed of each wheel. If any wheel begins to approach lock-up, 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 the wheel again begins to approach
lock-up. This cycle repeats until either the vehicle comes to a stop, the brake is released, or no wheels approach lock-up. With ETS, the EBCM
monitors the wheel spin slip through the front wheel speed sensors. If either of the front wheels begins to slip, the EBCM determines the desired wheel
torque needed to minimize front wheel spin. This information is sent to the Powertrain Control Module (PCM) via the serial data link. The PCM then
calculates a spark retard value to achieve the requested torque and upshifts the transmission if needed. Additionally, the EBCM monitors itself, each
input and each output for proper operation. If any system malfunction is detected, the EBCM will store a DTC in nonvolatile memory (DTCs will not
disappear if the battery is disconnected).
