Brake Fluid Pump: Description and Operation

Integrated Control Unit (ICU):

The Hydraulic Control Unit (HCU) contains 2 pump assemblies, one for the primary and one for the secondary hydraulic circuit of the brake system. Both pumps are driven by a common electric motor which is part of the HCU. The pumps draw brake fluid from the fluid accumulators to supply build pressure to the brakes during an ABS stop. The pump motor runs during the drive-off cycle as a check and during an ABS stop and is controlled by the Controller Antilock Brake (CAB). The Pump/Motor Assembly is not a serviceable item. If the pump/motor requires replacement the complete HCU (minus the CAB) must be replaced.