Vision V6-3.5L VIN F (1997)
Brake Fluid Pump: Description and Operation
HCU Pump/Motor
HYDRAULIC CONTROL UNIT PUMP MOTOR ASSEMBLY
The pump/motor assembly consists of an electric motor and a dual piston pump. The motor shaft inside the pump is designed as a cam in order to
drive both pistons. The pump picks up fluid from the accumulators to supply build pressure to the brakes during an ABS stop. The pump motor
only runs during an ABS stop and is controlled by the Controller Antilock Brake CAB from the pump/motor relay. The pump/motor assembly is
not a serviceable item. If the pump/motor requires replacement the complete HCU assembly must be replaced.
CIRCUIT OPERATION
Power for the ABS pump motor is supplied on circuit B82 from the ABS pump motor relay This circuit is HOT when the contacts in the relay are
CLOSED.
Ground for the motor is supplied on circuit Z1. This circuit terminates at the left front frame rail.
