RAM 3500 Truck 4WD L6-5.9L DSL Turbo VIN C (2002)
Electronic Brake Control Module: Description and Operation
Fig. 10 RWAL Cab
CONTROLLER ANTILOCK BRAKE
The Controller Antilock Brakes (CAB) is a microprocessor which handles testing, monitoring and controlling the ABS brake system operation.
The CAB functions are:
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Perform self-test diagnostics.
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Monitor the RWAL brake system for proper operation.
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Control the RWAL valve solenoids.
NOTE: If the CAB needs to be replaced, the rear axle type and tire revolutions per mile must be programed into the new CAB. For axle type refer
to Group 3 Differential and Driveline. To program the CAB refer to the Chassis Diagnostic Manual.
System Self-test
When the ignition switch is turned-ON the microprocessor RAM and ROM are tested. If an error occurs during the test, a DTC will be set into the
RAM memory. However it is possible the DTC will not be stored in memory if the error has occurred in the RAM module were the DTC's are
stored. Also it is possible a DTC may not be stored if the error has occurred in the ROM which signals the RAM to store the DTC.
CAB Inputs
The CAB continuously monitors the speed of the differential ring gear by monitoring signals generated by the rear wheel speed sensor. The CAB
determines a wheel locking tendency when it recognizes the ring gear is decelerating too rapidly. The CAB monitors the following inputs to
determine when a wheel locking tendency may exists:
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Rear Wheel Speed Sensor
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Brake Lamp Switch
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Brake Warning Lamp Switch
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Reset Switch
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4WD Switch (If equipped)
CAB Outputs
The CAB controls the following outputs for antilock braking and brake warning information:
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RWAL Valve
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ABS Warning Lamp
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Brake Warning Lamp