Mazda 6. Manual — part 43

DYNAMIC STABILITY CONTROL

P–15

P

COMBINE SENSOR

A6E692067650T05

Function

•

Yaw rate sensor and lateral-G sensor have been integrated to combine sensor.

•

The combine sensor is installed on the left side of the parking brake lever (L.H.D.), or right side of the parking
brake lever (R.H.D.) and detects vehicle yaw rate (vehicle cornering angle velocity) and lateral G, and transmits
the signal to the DSC HU/CM.

Structure/Operation

•

The output voltage characteristic for the combine sensor is 2.5 V when the vehicle is standing still, and changes
accordingly as yaw rate and lateral-G is formed.

•

Yaw rate is formed when the sensor detects a Coriolis force created by, and in proportion to, the rotation speed
of a rotating tuning fork.

•

Lateral G is formed when the sensor detects an inertial force created by, and in proportion to, a G force acting
on a silicon detection component.

Note

•

The Coriolis force: When an object on a rotating disc attempts to move toward the disc's center, force is
produced at a right angle to the object's intended path of travel. This results in the object's direction of
movement being unchanged from its original point of departure, and it not reaching the center. When
looking at this effect from outside the disc, it appears as force deflecting the object away from the center.
This appearance of force is called Coriolis force, and the object's actual direction of advance takes a
straight course.

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A6E6920T014

1

External view

2

Front of vehicle

3

Output voltage characteristic

4

Acceleration

5

Left cornering

6

Lateral-G

7

Right cornering

8

Output voltage characteristic

9

Left cornering

10

Yaw rate

11

Right cornering

P–16

DYNAMIC STABILITY CONTROL

DSC HU/CM

A6E692067650T09

Function

•

The integrated DSC HU/CM, which is compact and lightweight, highly reliable has been adapted.

•

The DSC HU/CM calculates the input signal of each sensor and controls each solenoid valve and the pump
motor (ON/OFF), adjusts fluid pressure to the caliper pistons, and activates each function of the DSC system
(ABS, Electronic Brakeforce Distribution (EBD), TCS, DSC and electrical brake assist).

•

The construction and operation of DSC hydraulic pressure mechanism is the same as that of the current 323
(BJ), except for the operation of electric brake assist system. (See 323 Workshop Manual Supplement 1704-1*-
00J.)

•

The DSC HU/CM outputs the engine torque control signal and vehicle speed signal through CAN line.

•

The DSC HU/CM also outputs vehicle speed signal through a hard wire.

Function

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BRAKE ASSIST CONTROL

A6E692067650T16

Function

•

During emergency braking, the DSC HU/CM increases brake fluid pressure by increasing the master cylinder
pressure, and therefore lessens the burden on the driver and enables use of a large braking force.

Operation

•

The DSC HU/CM uses the built-in brake fluid pressure sensor to monitor the rate at which the master cylinder
pressure changes, and it initiates brake assist when it determines, from the pressure change, that emergency
braking is occurring.

•

The DSC HU/CM calculates the caliper piston pressure, increases fluid pressure in the master cylinder above
the specified amount and, due to the change in master cylinder pressure, caliper piston pressure can be
increased.

•

In addition to normal brake fluid pressure, as each solenoid valve is switched, the pump motor is operated to
rotate the pump which increases brake pressure force in the caliper pistons.

•

Break assist is initiated at speeds of 17 km/h or above, and is inhibited at speeds of 5 km/h or below.

Function

Content

ABS control function

•

When braking, maintains direction stability during braking operation, secures
handling and provides shortened braking distance by control of brake fluid
pressure.

EBD (Electronic brakeforce distribution)
control

•

Prevents rear-wheel lockup through optimum control of normal brake fluid
pressure distribution to front and rear wheels in response to vehicle load,
condition of road surface and vehicle speed.

TCS control

•

Provides improved safety of start and acceleration performance by keeping
traction within limits of road surface friction in response to road and vehicle
speed conditions.

DSC control

•

Inhibits strong tendency of the vehicle to oversteer or understeer, by controlling
engine torque and braking on each wheel to provide assured vehicle stability.

Brake assist control

•

Controls the fluid of the caliper piston during emergency braking, provides
increased fluid pressure to each wheels.

Vehicle speed output

•

The value of the calculation from the 4 wheel speed sensors is output as a speed
signal to CAN line, and to wiper and washer switch, cruise actuator, audio unit,
auto leveling control unit by a hard wire.

Diagnostic system

•

Important parts in the DSC control have a self-detection function that, in the
event of any abnormality, illuminate each warning light to inform the driver of an
abnormality together with recording the DTC in the DSC unit.

•

When occurrence of an abnormality is judged by self-detection, cancels the
controls so as not to cause loss of driving safety.

DYNAMIC STABILITY CONTROL

P–17

P

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CONTROLLER AREA NETWORK (CAN)

A6E692067650T17

•

ABS (ABS/TCS) or DSC HU/CM transmit/received the information through the CAN. For detail information of
the CAN, see the “CONTROLLER AREA NETWORK.” (See

T–5 OUTLINE

.)

Transmit Information

•

Travelled distance

•

Wheel Speed
— Front Left
— Front right
— Rear left
— Rear right

•

Brake system status

•

Torque reduction request

•

Brake system configuration

Received Information

•

Engine conditions from PCM

•

Engine speed from PCM

•

Transmission/axle type from PCM

•

Tire circumference from PCM

•

Gear/change lever position from PCM

•

Brake system warning light condition (brake fluid level) from instrument cluster

•

ABS configuration from instrument cluster

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A6E6920T015

1

Normal brake mode

2

Brake assist reduction mode

3

Master cylinder

4

Stability control solenoid valve

5

Pressure-retention solenoid valve

6

Pressure-reduction solenoid valve

7

Pump motor

8

Traction switch solenoid valve

9

Pump

10

caliper piston

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ON-BOARD DIAGNOSTIC

OUTLINE

A6E697067650T03

•

The operation of the on-board diagnostic system for ABS (ABS/TCS) or DSC is essentially carried over from
that of the previous 323 (BJ) model except for the following. (See Mazda 323 Workshop Manual Supplement
1704-1*-99H.)
— Changed of DTC code, PID data monitor function, and active command function
— Eliminated TBS terminal of DLC

•

Using the WDS or equivalent with the ABS (ABS/TCS) or DSC HU/CM, allows for a 4-digit DTC display
function, a PID/DATA monitor function, and an active command modes function, and thus improves
serviceability.

Block diagram

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ON-BOARD DIAGNOSTIC

A6E6920T002

1

TCS (DSC) indicator light

2

TCS (DSC) OFF light

3

ABS warning light

4

Brake system warning light

5

Malfunction indication function

6

On-board diagnosis function

7

Serial communication

8

Memory function

9

Malfunction detection function

10

Data monitor function

11

Active command function

12

Fail-safe function

13

Input devices

14

Normal control area

15

Data link connector-2

16

WDS or equivalent

17

Hydraulic inspection function

18

Output devices