B4000 SE Regular Cab 4WD V6-4.0L OHV (1999)
Electronic Brake Control Module: Description and Operation
4WABS CONTROL MODULE
The 4WABS control module is mounted to the ABS hydraulic control unit.
It is an on-board diagnostic, nonrepairable unit consisting of two microprocessors and the necessary circuitry for their operation. The 4WABS control
module monitors system operation during normal driving as well as during anti-lock braking.
Anti-lock brake module operation is as follows:
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Under normal driving conditions, the microprocessor produces short test pulses to the solenoid valves that check the electrical system without any
mechanical reaction.
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Impending wheel lock conditions trigger signals from the 4WABS control module that open and close the appropriate solenoid valves. This results
in moderate pulsations in the brake pedal.
During normal braking, the brake pedal feel will be identical to a standard brake system.
Most faults which occur in the anti-lock brake system will be stored as a Diagnostic Trouble Code (DTC) in the keep-alive memory of the 4WABS
control module. The DTCs can be retrieved by following the on-board diagnostic procedures.
