#
ABS HU PART CONSTRUCTION/OPERATION

id041300185400

## Construction

• The ABS HU mainly consists of the inlet/outlet solenoid valves, pump motor (pump) and reservoir.

### Function Of Main Component Parts

Part name | Function
--- | ---
Inlet solenoid valve | • Adjusts the fluid pressure in each brake system according to ABS CM signals.
Outlet solenoid valve | • Adjusts the fluid pressure in each brake system according to ABS CM signals.
Reservoir | • Temporarily stores the brake fluid from the caliper piston to ensure smooth pressure reduction.
Pump | • Returns brake fluid stored in the reservoir back to the master cylinder.
Pump motor | • Operates the pump according to ABS CM signals.
Flow control valve* | • Shifts fluid flow from constricted paths during pressure reduce mode to suppress noise. (Only installed on the front system.)

  * :
[Applied VIN (assumed): JM0 DY10Y100 100001-108401,JM6 DY10*100 109001-]

### Hydraulic Circuit Diagram

## Operation

### During normal braking

  • During normal braking, the solenoid valves are not energized and all of them are off. When the brake pedal is depressed, brake fluid pressure is transmitted from the master cylinder, through the inlet solenoid valves, and then to the caliper piston. (The figure shows control for one front wheel only.)

Solenoid valve operation table

Inlet solenoid valve | Outlet solenoid valve | Pump motor, pump
--- | --- | ---
LF | RF | LR | RR | LF | RF | LR | RR
OFF (open) | OFF (closed) | Stopped

Hydraulic Circuit Diagram

### During ABS and EBD control

  • When wheel lock-up is about to occur, the inlet and outlet solenoid valves are energized and controlled in three pressure modes (increase, maintain, or reduction), thereby adjusting brake fluid pressure. Brake fluid during pressure reduction is temporarily stored in the reservoir and afterwards the pump motor operates the pump to return the fluid to the master cylinder. (The figure shows control for one front wheel only.)

Solenoid valve operation table

| Inlet solenoid valve | Outlet solenoid valve | Pump motor, pump
--- | --- | --- | ---
LF | RF | LR | RR | LF | RF | LR | RR
During pressure increase mode | OFF (open) | OFF (closed) | Stopped
During pressure maintain mode | ON (closed) | OFF (closed) | Stopped
During pressure reduction mode | ON (closed) | ON (open) | Operation

Hydraulic Circuit Diagram