Mazda X-5. Manual - part 60

ANTILOCK BRAKE SYSTEM 

04–13–3

04–13

ABS HU/CM CONSTRUCTION

E5U041343750N01

• A high reliability, reduced size and weight ABS 

HU/CM, integrating both the ABS HU and ABS 
CM, has been adopted.

End Of Sie

ABS HU PART FUNCTION

E5U041343750N02

• The ABS HU adjusts the fluid pressure to the caliper pistons by controlling (on/off) each solenoid valve and 

pump motor according to signals from the ABS CM.

End Of Sie

ABS HU PART CONSTRUCTION/OPERATION

E5U041343750N03

Construction

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

Function of main component Parts

E5U413ZS5002

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 reserve back to the master cylinder.

Pump motor

• Operates the pump according to ABS CM signals.

ANTILOCK BRAKE SYSTEM 

04–13–4

Hydraulic circuit diagram

Operating
Normal braking or pressure increase mode

• During normal braking or pressure increase mode the inlet and outlet solenoid valves are not energized: the 

inlet solenoid valve is open and the outlet solenoid valve is closed. Brake fluid pressure from the master 
cylinder flows through the inlet solenoid valve and is transmitted to the caliper piston. At this time, the pump 
motor does not operate. (Description for single front wheel only)

Solenoid valve operation table

RF

LR

RR

LF

MASTER CYLINDER

DAMPER CHAMBER

RESERVOIR

PUMP MOTOR

PUMP

OUTLET 
SOLENOID 
VALVE

RESERVOIR

INLET 
SOLENOID 
VALVE

OUTLET 
SOLENOID 
VALVE

OUTLET 
SOLENOID 
VALVE

OUTLET 
SOLENOID 
VALVE

INLET 
SOLENOID 
VALVE

E5U413ZS5003

Inlet solenoid 

valve

Outlet solenoid 

valve

Pump motor, 

pump

OFF (open)

OFF (closed)

Stopped

ANTILOCK BRAKE SYSTEM 

04–13–5

04–13

Pressure reduction mode

• During pressure reduction mode, when the wheels may possibly lock-up due to emergency braking or similar, 

the inlet solenoid valve closes and the outlet solenoid valve opens. The brake fluid being applied to the caliper 
piston flows out through the outlet solenoid valve into the reserve tank, thereby decreasing pressure. During 
this operation, the pump motor operates, returning the brake fluid stored in the reserve tank to the master 
cylinder. (Description for single front wheel only)

Solenoid valve operation table

MASTER CYLINDER

DAMPER CHAMBER

RESERVOIR

PUMP MOTOR

PUMP

INLET 
SOLENOID 
VALVE

OUTLET 
SOLENOID 
VALVE

CALIPER PISTON

PRESSURE INCREASE MODE

E5U413ZS5004

Inlet solenoid 

valve

Outlet solenoid 

valve

Pump motor, 

pump

ON (closed)

ON (open)

Operating

MASTER CYLINDER

DAMPER CHAMBER

RESERVOIR

PUMP MOTOR

PUMP

INLET 
SOLENOID 
VALVE

OUTLET 
SOLENOID 
VALVE

CALIPER PISTON

PRESSURE REDUCTION MODE

E5U413ZS5005

ANTILOCK BRAKE SYSTEM 

04–13–6

Pressure maintain mode

• During pressure maintain mode, both the inlet and outlet solenoid valves are closed. The path for the brake 

fluid being applied to the caliper piston is blocked and brake fluid pressure is maintained. (Description for single 
front wheel only)

Solenoid valve operation table

End Of Sie

ABS CM PART FUNCTION

E5U041343750N04

• The ABS CM detects the vehicle wheel speeds based on the signals from the four ABS wheel- speed sensors. 

The CM calculates the rotation condition of each wheel from the relation between the detected vehicle wheel 
speed and the estimated (based on the detected speed) vehicle speed from there on. It then accordingly 
controls brake fluid pressure to each wheel to prevent lock-up.

Function Table

End Of Sie

Inlet solenoid 

valve

Outlet solenoid 

valve

Pump motor, 

pump

ON (closed)

OFF (closed)

Stopped

PRESSURE MAINTAIN MODE

MASTER CYLINDER

DAMPER 
CHAMBER

RESERVOIR

PUMP MOTOR

PUMP

INLET 
SOLENOID 
VALVE

OUTLET 
SOLENOID 
VALVE

CALIPER PISTON

E5U413ZS5006

Function name

Contents

ABS control function

• Controls brake fluid pressure when braking to maintain directional 

stability, ensure steerability and reduce stopping distance.

Electronic brakeforce distribution (EBD) control 
function

• Constantly controls proper distribution of brake fluid pressure to the front 

and rear wheels according to vehicle load, road surface and vehicle 
speed conditions to prevent early lock-up of the rear wheels.

CAN signal function

• Outputs the wheel speed signal and ABS system warning control data 

via CAN lines.

On-board diagnostic system

• Main components of the ABS control system have a self-diagnosis 

function. In case a malfunction occurs, warning lights illuminate to alert 
the driver, and at the same time a DTC is stored in the ABS HU/CM.

• When a malfunction is determined as a result of on-board diagnosis, 

system control is suspended or limited to prevent any dangerous 
situation while driving.