Seville V8-273 4.5L (1989)
Electronic Brake Control Module: Description and Operation
EBCM Inputs
The ignition enable input receives battery voltage whenever the ignition switch is in the RUN position. Upon receiving an ignition enable input, the
EBCM begins its self-checks.
CRANK SENSE
A crank sense input is provide to the EBCM which goes high (12 volts), when the ignition switch is moved to the START position. When the crank
sense input is high, the EBCM commands itself, internally, to shut off until engine start is completed.
BRAKE LIGHT SWITCH
The EBCM also receives a 12 volt signal from the brake light switch whenever the brake pedal is depressed. The brake light switch input alerts the
EBCM when the brakes are applied and increases its sensitivity to wheel speed sensor inputs.
WHEEL SPEED SENSORS
The EBCM continuously receives wheel speed information from each of the four wheel speed sensors. The sensors one at each wheel, generate a
signal when the wheel is turned. This signal is created by passing a toothed sensor ring past a stationary sensor which consists of a permanent magnet and
coil. A specified air gap must be maintained between the sensor face and the toothed sensor ring.
LOW FLUID & LOW PRESSURE
The low brake fluid and low pressure inputs consist of a continuous loop circuit which runs through the fluid level sensor and the pressure switch.
DIAGNOSTIC ENABLE
The diagnostic enable input is a circuit which runs from the EBCM to the assembly line diagnostic link (ALDL), pin G on 1998 models or pin H on
1989-90 models. When this line is grounded, the EBCM enters the diagnostic mode.
