Mitsubishi Outlander (2013+). Manual — part 65

CONSTRUCTION DIAGRAM

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-13

HSA function state transition diagram (Overview)

NOTE:

.

•

ASC-ECU judges the inclination angle of the slope according to the G and yaw rate sensor output.

•

When either of the following conditions is satisfied, the mode is shifted to the forcible termination mode,
and HSA function control is terminated.

•

The parking brake operation is detected.

•

The shift lever operation to the shift or selector position other than the uphill direction driving is

detected (Forward uphill driving: shift or selector position other than "D"

*

, Reverse uphill driving: shift

or selector position other than "R").

•

The accelerator pedal and brake pedal are depressed at the same time.

•

The wheel speed sensor pulse is generated (When the vehicle moved)

•

The engine is stopped by engine stall, etc.

*:When uphill driving, if shift position is "N" position, HSA function is operated

HSA function control activated

ASC-ECU judges that the HSA operation condition is
satisfied. When the driver releases the brake pedal,
ASC-ECU maintains the brake wheel cylinder pres-
sure and waits.

FLUID PRESSURE HOLD MODE

By closing the cut valve, ASC-ECU maintains the
brake wheel cylinder pressure of the time when the
brake pedal is depressed, to prevent the vehicle from
moving backward.

AC809431

Fluid pressure
hold mode

When the conditions above are met

Forcible termination
mode

- Steep uphill

- The accelerator pedal is not depressed

Release of depressed brake pedal

The fluid pressure hold mode is kept for
approx. two seconds

Start mode

The accelerator pedal
is depressed

HSA function
control activated

HSA function control
not activated

The start mode is continued for
approx. 1.5 seconds

Depressurization is
complete

AC

Depressurization is
complete

- The vehicle has been stopped by depressing the brake during uphill driving

CONSTRUCTION DIAGRAM

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-14

START MODE

ASC-ECU releases the brake wheel cylinder pres-
sure maintained by the cut valve, depending on the
engine torque generated by depressing the accelera-
tor pedal.

FORCIBLE TERMINATION MODE

ASC-ECU immediately releases the brake wheel cyl-
inder pressure maintained by the cut valve and termi-
nates HSA function control.

BRAKE ASSIST (BA) CONTROL

Operation description

• If an emergency brake is determined by the brake

pedal depression speed and force, the brake
assist works to increase the braking force the
drivers produce. [The braking force is not
increased more than the brake performance (the
friction force between the road surface and the
tyres) .]

• The brake assist is completed when the brake

pedal is released or the vehicle is stopped.

fail-safe function

The brake assist mechanism does not work when the
ABS warning lamp illuminates.

Brake assist operation

FAIL-SAFE AND DIAGNOSTIC FUNCTIONS

ASC-ECU constantly monitors the input and output
signals. If an error is detected in the system,
ASC-ECU sends a fail signal and the corresponding
indicator lamp is illuminated or blinks. Various con-
trols are processed depending on the cause of mal-
function as shown below.
ASC-ECU has the following functions for easier sys-
tem checks.

• Diagnosis code set

• Service data output

• Actuator test

• Freeze frame data output

All the above items can be diagnosed using
M.U.T.-III.

CALIBRATION

After the steering wheel sensor and hydraulic unit
(integrated with ASC-ECU and G & yaw rate sensor)
have been replaced with new ones, calibration must
be performed using M.U.T.-III*.

NOTE:

.

•

M.U.T.-III uses the ABS data list.

•

*: For calibration, refer to Workshop Manual.

AC903511AC

Brake pedal
depression force

Braking force

Emergency brake (determined)

Elapsed time

Elapsed time

With brake assist

Without brake assist

DESCRIPTION OF CONSTRUCTION AND OPERATION

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-15

DESCRIPTION OF CONSTRUCTION AND OPERATION

M2355002000563

STABILITY CONTROL OPERATION

ASC-ECU receives various kinds of information from
the engine-ECU, 4WD-ECU, ETACS-ECU,
CVT-ECU, steering wheel sensor, G & yaw rate sen-
sor, and wheel speed sensor. When ECU determines
the vehicle runs in the oversteer or understeer direc-
tion based on the signal sent from these sensors,
ASC-ECU drives each valve and pump motor and
controls the braking force to be applied to the
wheels.

When the system increases the fluid pressure auto-
matically, it closes the cut valve to shut off the pres-
sure line to the suction valve, and drives the pump
motor. For example, when the vehicle runs in the
oversteer direction while turning to the right,
ASC-ECU supplies the brake fluid from the pump to
the front left wheel to apply the braking force on it.
ASC-ECU, the engine ECU, and 4WD-ECU commu-
nicate with each other via CAN. When the accelera-
tor pedal is depressed too far, the signal requesting
the engine output reduction is sent to the engine
ECU. Depending on the situation, 4WD control
amount limitation signal is sent to the ASC-ECU to
secure the ASC controllability.

When brake fluid pressure decreases during ABS operation

The brake fluid supplied from the wheel cylinder is
stored in the low pressure accumulator. Then, the
stored brake fluid is returned to the master cylinder
by driving the pump using the motor.

ACC00363AB

Low pressure
accumulator

Pump

Motor

Suction
damper

Damping
chamber

Wheel
cylinder
(Rear)

Wheel
cylinder
(Front)

Brake fluid flow

Hydraulic unit

Outlet valve

Outlet valve

Inlet valve

Inlet valve

Suction valve

Cut valve

Pressure sensor

Master cylinder

DESCRIPTION OF CONSTRUCTION AND OPERATION

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-16

VALVE CONDITION

When brake fluid pressure is held by ABS

The system closes the inlet valve and outlet valve to
hold the brake fluid pressure in the wheel cylinder. If
the brake fluid is stored in the low pressure accumu-
lator, the brake fluid is returned to the master cylinder
by driving the pump using the motor.

VALVE CONDITION

Item

Power status

Open/Close

Cut valve

OFF

Open

Suction valve

OFF

Closed

Inlet valve

ON

Closed

Outlet valve

ON

Open

ACC00363AC

Low pressure
accumulator

Pump

Motor

Suction
damper

Damping
chamber

Brake fluid flow

Hydraulic unit

Outlet valve

Outlet valve

Inlet valve

Inlet valve

Suction valve

Cut valve

Pressure sensor

Master cylinder

Wheel
cylinder
(Rear)

Wheel
cylinder
(Front)

Item

Power status

Open/Close

Cut valve

OFF

Open

Suction valve

OFF

Closed

Inlet valve

ON

Closed

Outlet valve

OFF

Closed