Mazda X-5. Manual - part 65

 

  Index      Mazda     Mazda X-5 - service repair manual 2006 year

 

Search            

 

 

 

 

 

 

 

 

 

Content   ..  63  64  65  66   ..

 

 

Mazda X-5. Manual - part 65

 

 

DYNAMIC STABILITY CONTROL 

04–15–11

04–15

DSC CM PART FUNCTION

E5U041543750N04

• The DSC CM makes calculations using signals input from each sensor, outputs a brake fluid pressure control 

signal to the DSC HU to actuate DSC system functions and outputs an engine output control signal to the PCM.

• The DSC HU/CM controls the following functions:

Function Table

Function name

Contents

ABS control function

• Controls brake fluid pressure when braking to maintain directional 

stability, ensure steerability and reduce stopping distance.

EBD (Electronic Brakeforce Distribution) 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.

TCS control function

• Controls traction to within the road surface friction limit and according to 

road and driving conditions to improve starting and acceleration 
performance, and safety.

DSC control function

• Suppresses strong over-steer and under-steer tendencies when turning 

by controlling engine output and braking of each wheel to assure driving 
safety.

CAN signal function

• Transmits the wheel speed signal to the PCM using CAN 

communication.

On-board diagnostic system

• A function that allows important parts of the DSC control system to 

perform self-diagnosis. In case a malfunction occurs, the warning lights 
illuminate to alert the driver, and at the same time a DTC is stored in the 
DSC HU/CM.

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

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

DYNAMIC STABILITY CONTROL 

04–15–12

Block Diagram

End Of Sie

ABS CONTROL FUNCTION

E5U041543750N05

• ABS control is basically the same as that for vehicles with ABS. However, fluid pressure in each wheel is under 

independent control in this system.

End Of Sie

EBD CONTROL FUNCTION

E5U041543750N06

• EBD control has an independent control system for the front and rear wheels, as well as vehicles with ABS, 

which constantly and properly distributes brake fluid regardless of vehicle weight (number of passengers).

End Of Sie

INPUT

ABS WHEEL-
SPEED SENSOR

BRAKE SWITCH

PCM

ENGINE SPEED

THROTTLE 
OPENING ANGLE

OUTPUT TORQUE/ 
TORQUE REDUCTION 
INHIBITED

DSC OFF SWITCH

STEERING 
ANGLE SENSOR

COMBINED SENSOR

YAW RATE 
SENSOR

LATERAL-G 
SENSOR

BRAKE FLUID 
PRESSURE SENSOR

CM INTERNAL CALCULATION

WHEEL-SPEED 
CALCULATION

ESTIMATED VEHICLE 
SPEED CALCULATION

BRAKE OPERATING 
CONDITION DETERMINATION

ENGINE SPEED 
CALCULATION

THROTTLE OPENING 
ANGLE DATA ASSIMILATED

OUTPUT TORQUE/
TORQUE RESUCTION 
INHIBITED DATA ASSIMILATED

DSC OFF REQUIREMENT 
DETERMINED

YAW RATE 
CALCULATION

LATERAL-G 
CALCULATION

MASTER CYLINDER FLUID 
PRESSURE CALCULATION

DSC 
CONTROL 
AMOUNT

TCS 
CONTROL 
AMOUNT

EBD 
CONTROL 
AMOUNT

ABS 
CONTROL 
AMOUNT

OUTPUT

PUMP 
MOTOR

FRONT 
SOLENOID 
VALVE

REAR 
SOLENOID 
VALVE

PCM

TRACTION 
CONTROL 
SOLENOID 
VALVE

STABILITY 
CONTROL 
SOLENOID 
VALVE

E5U415ZS5009

DYNAMIC STABILITY CONTROL 

04–15–13

04–15

TCS CONTROL OUTLINE

E5U041543750N07

• TCS control actuates torque reduction through throttle, fuel cut and ignition timing control, as well as using 

brake control to control traction.

Note

• Brake control: Brake fluid pressure from the hydraulic unit to the slipping driving wheel is increased, 

operating the brake and preventing drive wheel slip.

Features

• The left and right wheels are controlled at the same time by throttle, fuel cut and ignition timing control. 

Therefore, when the road surface friction coefficients differ between the left and right wheels, proper torque 
reduction cannot be performed separately for each wheel. When this occurs, torque reduction is performed by 
independent left and right wheel brake control, providing much stable vehicle control.

Block Diagram

End Of Sie

TCS CONTROL OPERATION

E5U041543750N08

• TCS control detects a slipping drive wheel using the following signals, sends a torque reduction request signal 

to the PCM and, at the same time, controls the solenoid valves and pump motor in the DSC HU/CM.

— Vehicle wheel speed signals from the front and rear ABS wheel-speed sensors

— Engine torque signal from the PCM

— Steering angle signal from the steering angle sensor

— Yaw rate and lateral-G signals from the combined sensor

— Fluid pressure signals from the brake fluid pressure sensors

End Of Sie

BRAKE FLUID 
PRESSURE 
SENSOR

DSC HU/CM

ABS WHEEL-SPEED 
SENSOR (LF)

ABS WHEEL-SPEED 
SENSOR (RF)

ABS WHEEL-SPEED 
SENSOR (LR)

ABS WHEEL-SPEED 
SENSOR (RR)

STEERING ANGLE 
SENSOR

COMBINED 
SENSOR

CPU

CM

HU

SOLENOID 
VALVE

PUMP 
MOTOR

PCM

CALIPER PISTON 
(RR)

CALIPER PISTON 
(LR)

E5U415ZS5010

DYNAMIC STABILITY CONTROL 

04–15–14

DSC CONTROL OUTLINE

E5U041543750N09

• While a vehicle normally turns safely in response to steering operation, there are instances when the limits of 

tire lateral grip is surpassed due to road surface conditions or vehicle speed, and the influence of evasive 
steering to avoid an accident or similar situations.

• Tires surpassing lateral grip exhibit one of the following conditions:

— Strong oversteer tendency: The rear wheels are relatively losing their grip as compared to the front wheels 

— Strong understeer tendency: The front wheels are relatively losing their grip as compared to the rear 

wheels 

• DSC operates at vehicle speeds of 10 km/h {6.2 mph} or more in the conditions described above, controlling 

engine output and wheel braking to suppress oversteer and understeer tendencies.

Vehicle Condition Determination

• The vehicle speed, steering angle, lateral-G and yaw rate are detected by the sensors and used in calculations 

by the DSC HU/CM to determine the vehicle condition. Then, depending on the difference between the target 
yaw rate, calculated with the values input from each sensor, and the value detected by the yaw rate sensor, an 
oversteer or understeer tendency can be determined.

Oversteer Tendency Determination

• When turning, if the actual vehicle yaw rate is larger than the target yaw rate (the yaw rate that should normally 

be formed as determined by the steering angle and vehicle speed), it means that the vehicle is in or about to be 
in a spin. Therefore the vehicle is determined to have an oversteer tendency.

Understeer Tendency Determination

• When turning, if the actual vehicle yaw rate is less than the target yaw rate (the yaw rate that should normally 

be formed as determined by the steering angle and vehicle speed), it means that the vehicle is not properly 
turning. Therefore the vehicle is determined to have an understeer tendency.

End Of Sie

YAW MOMENTUM

UNDERSTEER CONDITION 
LINE OF TRAVEL

TARGET YAW RATE 
LINE OF TRAVEL

OVERSTEER CONDITION 
LINE OF TRAVEL

E5U415ZS5011

 

 

 

 

 

 

 

Content   ..  63  64  65  66   ..