Mitsubishi Evolution X. Manual — part 156

CONSTRUCTION DESCRIPTION

TSB Revision

ACTIVE SKID CONTROL SYSTEM (ASC)

35C-9

ASC OFF switch operation and system operation

NOTE:

.

•

When the ASC OFF switch is pressed and held for 15 sec-
onds or more, the ASC function is turned ON.

•

The ASC control is available when the vehicle speed is 15
km/h or more.

Item

ASC ON

ASC OFF

ASC OFF (AYC brake
control OFF)

EBD function

Enabled

Enabled

Enabled

ABS function

Enabled

Enabled

Enabled

TCL function

Enabled

Prohibited

Prohibited

Skid control function

Enabled

Prohibited

Prohibited

AYC function (brake
control)

Enabled

Enabled

Prohibited

AC707871

ASC ON

(Activated)

ASC OFF

ASC OFF

(AYC brake control OFF)

: Press and hold (3 seconds or more)

: Short press

AB

CONSTRUCTION DESCRIPTION

TSB Revision

ACTIVE SKID CONTROL SYSTEM (ASC)

35C-10

ACTUATOR

M2355001200144

.

HYDRAULIC UNIT

With the hydraulic unit, the brake wheel cylinder
pressure sensor is added to each wheel compared
with the conventional ASC system, achieving more
precise brake force control.
NOTE: For the internal hydraulic circuit of the
hydraulic unit, refer to

P.35C-14

.

.

ASC OPERATION DISPLAY, ASC
WARNING DISPLAY, ASC OFF LIGHT,
ASC OFF DISPLAY

The ASC system illuminates or flashes the ASC
operation display, ASC warning display, ASC OFF
light, and ASC OFF display in the following operation
patterns, and informs the driver of the ASC system
status.

ASC operation display

• Flashes at 2-Hz interval during the ASC control.

• Flashes at 2-Hz interval during the TCL control.

ASC warning display

• Turns ON when the system malfunction occurs.

ASC OFF display and ASC OFF light

• Illuminates when the system is stopped by the

ASC OFF switch operation.

ASC operation display, ASC warning display, ASC OFF light, ASC OFF display illumination and

flashing patterns

State

ASC operation
display

ASC warning
display

ASC OFF light ASC OFF

display

Normal

Normal

−

−

−

−

ASC operated

Flashing (2 Hz) −

−

−

TCL operated

Flashing (2 Hz) −

−

−

While the system
is stopped by ASC
OFF switch
operation (short
press for once)

−

−

ON

−

While the system
is stopped by ASC
OFF switch
operation (long
press for 3
seconds)

−

−

ON

ON

Abnormal

ASC malfunction

−

ON

ON

−

TCL malfunction

−

ON

ON

−

Scan tool
connection

Actuator not
operated

−

−

−

−

Actuator operated −

ON

ON

−

CONSTRUCTION DESCRIPTION

TSB Revision

ACTIVE SKID CONTROL SYSTEM (ASC)

35C-11

ASC-ECU

M2357000100151

• This ECU incorporates the ABS function, EBD

function, skid control function, and TCL function.

• The hydraulic units of the ASC and TCL systems

employ the automatic pressurization function
compared with the conventional ABS system.
These systems also incorporate the G and yaw
rate sensor, steering wheel sensor, master cylin-
der pressure sensor (integrated with hydraulic
unit), and wheel cylinder brake fluid pressure
sensor (integrated with hydraulic unit).

EXAMPLE OF ACTIVE SKID CONTROL OPERATION

ASC-ECU detects the vehicle movement based on
information from various sensors, and calculates the
ideal vehicle movement model. ASC-ECU compares
the actual vehicle movement with the ideal vehicle
movement model, and controls the brake of specific
wheel to approximate the vehicle movement to the
ideal vehicle movement model by generating a yaw
moment to the vehicle in order to suppress the side
slip (spin and drift-out).

.

Example of control

The skid control function controls the vehicle attitude
by creating a yaw moment to the vehicle from alter-
ing the balance between the wheel's braking force
and cornering force.

.

AC313359AB

Creating a rotational moment

Creating a restorative moment

Braking force
increase

Braking force
increase

CONSTRUCTION DESCRIPTION

TSB Revision

ACTIVE SKID CONTROL SYSTEM (ASC)

35C-12

Example of the effect of control

For example, on a slippery surface, if the vehicle
tends to drift-out contrary to the driver's intention, a
yaw moment (rotational moment) is created to
restrain the drift-out by an increase of rear-inside
wheel braking force. On the other hand, when the
vehicle tends to spin, a yaw moment (restorative
moment) is created to restrain the spin by an

increase of front-outside wheel braking force. Fur-
thermore, when it is determined that the vehicle is
over-speeding, safe and stable cornering is ensured
by a reduction of engine output to decelerate the
vehicle.

.

Joint control

The skid control function communicates the data,
necessary for control of each function, with the ABS
function and TCL function, and performs the control
in coordination with the functions.

AC601970

Drift-out suppression

Spin suppression

Prevents drift-out caused
by side slip of front wheels

AC

Prevents spin caused
by side slip of rear wheels

Control system

Control content

ABS

Even during the skid control operation, ABS performance is improved
by the joint operation with the skid control.

TCL

During acceleration, engine output is governed through a joint
operation with the skid control.