Mazda Training manual — part 88

Dynamic Driving Safety Systems

ABS

Pressure Increase Mode

•

When the CM detects that the wheel slip decreases below a specified value, it increases
the brake force to that wheel, in order to keep the wheel slip in the specified range.

•

It deactivates the inlet and outlet solenoid valve and the pump. Thus, the pressure
increase is performed in the same way as during normal braking, the brake pressure is
increased by the driver’s foot, still pressing the brake pedal.

Inlet solenoid valve

Outlet solenoid valve

Pump motor

OFF (open)

OFF (closed)

OFF (stopped)

L2003_T02004

•

These three modes are repeated as required until either: the brake pedal is released,
the speed of the vehicle is below the specified value for ABS operation (approx. 5...15
km/h, depending on the vehicle) or the wheel slip does not exceed the specified value
anymore.

L2003_02008

X Time

2 Calculated

vehicle

speed

Y1 Speed

3 Pressure

increase

Y2

Solenoid valve control

4

Pressure hold

Y3

Brake fluid pressure

5

Pressure reduction

1 Wheel

speed

Curriculum Training

02-11

ABS

Dynamic Driving Safety Systems

Servicing

•

The ABS HU contains delicate mechanical parts. If foreign materials get into the
component the ABS may fail to operate. Also, it will likely become extremely difficult to
find the location of the malfunction in the event that the brakes operate but the ABS
does not. Make sure foreign materials do not get inside when servicing the ABS (e.g.
brake fluid replacement, pipe removal).

•

To avoid trouble coming from the hydraulic system of the ABS and the brake it is best to
protect the whole system with a regular exchange of brake fluid and flushing of the
hydraulic ABS unit.

NOTE: To avoid that the HU runs dry and air enters the HU, always install apropriate

closing covers when removing hydraulic lines.

Bleeding

NOTE: In most cases it is not necessary to bleed the HU with the aid of the M-MDS during

exchange of the brake fluid. Always follow the procedure of the corresponding W/M
(Workshop Manual).

•

If the ABS HU needs to be flushed or bled, it is necessary to switch on the pump and the
outlet valves.

NOTE: Always perform the manual bleeding procedure before performing any bleeding

procedure with the aid of the M-MDS

•

Connect the brake-bleeding device with the brake fluid reservoir ensuring that fresh
brake fluid will get to the HU.

•

For Mazda2 and Tribute the M-MDS provides the “ABS Service Bleed” function.
Connect the M-MDS with DLC2 and select

Æ 16PINDLC Æ Toolbox Æ Chassis Æ

Braking

Æ ABS Service Bleed and follow the screen instructions

02-12 Curriculum

Training

Dynamic Driving Safety Systems

ABS

•

For models the M-MDS does not provide a service bleed function, ABS valves and the
ABS pump can be activated via the Simulation Test Mode available in the DataLlogger
menu. Connect the M-MDS and select

Æ Toolbox Æ Datalogger Æ Modules Æ ABS

•

Then select PIDs as displayed below.

•

To start the activation of the valve and the pump in the HU:

–

Select and activate

Æ ABS_POWER

–

Select and activate the outlet solenoid valve of the corresponding brake calliper a
bleeding bottle is connected with (here it is the left front side)

Æ LF_OUTLET and

PMP_MOTOR

NOTE: To prevent the ABS unit from overload, the solenoid valves and pump motor must

not be activated permanently when bleeding. Depending on the model, the pump
motor and the solenoid valves are either automtically deactivated 10 seconds after
beeing activated with the aid of the M-MDS or they must be deactivated manually.

L2003_02052

•

Repeat the procedure for each outlet valve.

Curriculum Training

02-13

ABS

Dynamic Driving Safety Systems

Diagnostics

•

The HU/CM can be checked by:

–

Reading out DTCs

–

Checking voltage signals

–

Monitoring / Activating the corresponding PIDs (see below)

NOTE: The ABS warning light might stay illuminated after deleting DTCs, until the unit

performed a self test. Therefore it is necessary to perform a test drive after deleting
DTCs.

PID

Definition Unit/Condition

BOO_ABS

Brake switch

ON/OFF

CCNTABS

Number of detected DTCs

-

LR_OUTLET#

LR ABS pressure outlet solenoid valve

ON/OFF

LR_INLET#

LR ABS pressure inlet solenoid valve

ON/OFF

LR_WSPD

LR ABS wheel-speed sensor input

km/h, mph

RR_INLET#

RR ABS pressure inlet solenoid valve

ON/OFF

RR_OUTLET#

RR ABS pressure outlet solenoid valve

ON/OFF

RR_WSPD

RR ABS wheel-speed senosr input

km/h, mph

LF_INLET#

LF ABS pressure inlet solenoid valve

ON/OFF

LF_OUTLET#

LF ABS pressure outlet solenoid valve

ON/OFF

LF_WSPD

LF ABS wheel-speed sensor input

km/h, mph

RF_INLET#

RF ABS pressure inlet solenoid valve

ON/OFF

RF_OUTLET#

RF ABS pressure outlet solenoid valve

ON/OFF

RF_WSPD

RF ABS wheel-speed sensor input

km/h, mph

PMP_MOTOR#

ABS motor

ON/OFF

L2003_T02006

NOTE: Depending on the model, the availability of the PIDs varies. In addition, different PID

names may be used for identical parameters (see W/M).

Replacement

•

A new HU is usually delivered pre filled. Nevertheless, the brake system must be bled
according to the W/M.

•

A new CM must be configured (except for Mazda2 (DY) and B-Series (UN)) with the aid
of the M-MDS, via the option “Programmable Module Installation” (refer to W/M). If a
new DSC HU/CM has been installed, additional initialisation procedures of the sensors
must be performed (refer to W/M).

02-14 Curriculum

Training