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.
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