Mitsubishi Evolution X. Manual — part 152

GENERAL DESCRIPTION

TSB Revision

FOUR-WHEEL ANTI-LOCK BRAKE SYSTEM (4ABS)

35B-3

CONSTRUCTION DIAGRAM

AC708736

CHECK

SERVICE
REQUIRED

AB

9

11

1

1

2

2

13

5

6, 7, 8, 14

3

4

10

12

GENERAL DESCRIPTION

TSB Revision

FOUR-WHEEL ANTI-LOCK BRAKE SYSTEM (4ABS)

35B-4

MAIN COMPONENTS AND FUNCTIONS

.

Parts name

No. Functional description

Sensor

Wheel speed sensor

1

Outputs the frequency pulse signal in proportion to the
rotation speed of each wheel to ASC-ECU.

Magnetic encoder for
wheel speed detection

2

When the magnetic encoder for wheel speed detection
(a plate on which north and south pole sides of the
magnets are arranged alternately) rotates, the wheel
speed sensor outputs frequency pulse signal in
proportion to each wheel speed.

Stop light switch

3

Outputs the signal indicating whether the brake pedal
is depressed or not to ASC-ECU.

G and yaw rate sensor

4

Detects the yaw rate and longitudinal/lateral
acceleration of a vehicle, then outputs the signal to
ASC-ECU via the CAN line.

Steering wheel sensor

5

Detects the steering angle of steering wheel, and
outputs the signal to ASC-ECU via the CAN bus line.

Master cylinder pressure
sensor

6

Integrated into the hydraulic unit, converts the signal of
brake fluid pressure in master cylinder to the voltage
value, then outputs the value to ASC-ECU.

Wheel cylinder pressure
sensor

7

Integrated into the hydraulic unit, converts the signal of
brake fluid pressure in wheel cylinder of each wheel to
the voltage value, then outputs the value to ASC-ECU.

Actuator

Hydraulic unit

8

Drives the solenoid valve using the signal from
ASC-ECU, and controls the brake fluid pressure for
each wheel.

ABS warning light

9

Informs the driver of the system status by illuminating,
flashing, or turning off the warning light according to
the signal from ASC-ECU.

ABS warning display

10

Informs the driver of the system status by illuminating
or turning off the warning light according to the signal
from ASC-ECU.

Brake warning light

11

Used as the warning light for the parking brake, brake
fluid level, and EBD control. Informs the driver of the
system status by illuminating or turning off the warning
light according to the signal from ASC-ECU.

Brake warning display

12

Used as the warning light for the brake fluid level and
EBD control. Informs the driver of the system status by
illuminating or turning off the warning light according to
the signal from ASC-ECU.

Data link connector

13

Outputs the diagnostic trouble code and establishes
the communication with the scan tool.

ASC control unit (ASC-ECU)

14

Controls the actuators (described above) based on the
signals coming from each sensor.
Controls the self-diagnostic functions and fail-safe
functions.
Controls diagnostic function (Compatible with scan
tool).

CONSTRUCTION DESCRIPTION

TSB Revision

FOUR-WHEEL ANTI-LOCK BRAKE SYSTEM (4ABS)

35B-5

SYSTEM CONFIGURATION

Refer to GROUP 35C

− General Description

P.35C-2

.

.

ABS ELECTRICAL DIAGRAM

Refer to GROUP 35C

− General Description

P.35C-2

.

CONSTRUCTION DESCRIPTION

SENSOR

M2351001000687

WHEEL SPEED SENSOR

The wheel speed detecting section is a kind of a
pulse generator. It consists of the magnetic encoder
for wheel speed detection (plate on which north and
south pole sides of the magnets are arranged alter-
nately) which rotates at the same speed of the wheel
and the wheel speed sensor (semiconductor sensor).
This sensor outputs frequency pulse signals in pro-
portion to the wheel speed.

The front wheel speed detecting section consists of
the front wheel speed sensor mounted on the
knuckle and the magnetic encoder for wheel speed
detection which is press-fitted together with the oil
seal to the front wheel bearing. The rear wheel
speed detecting section consists of the rear wheel
speed sensor mounted on the knuckle assembly and
the magnetic encoder for wheel speed detection
which is press-fitted together with the oil seal to the
rear wheel bearing.

G AND YAW RATE SENSOR

This sensor is installed under the instrument panel center
lower, and detects the yaw rate as well as the lateral and longi-
tudinal acceleration of the vehicle.

AC507376AB

FRONT

REAR

Front wheel speed sensor

Rear wheel speed sensor

Encoder for wheel speed detection

Encoder for wheel speed detection

AC613534

AB

SRS-ECU

G&yaw rate sensor

CONSTRUCTION DESCRIPTION

TSB Revision

FOUR-WHEEL ANTI-LOCK BRAKE SYSTEM (4ABS)

35B-6

STEERING WHEEL SENSOR

The steering wheel sensor is mounted to the column switch,
and detects the rotational angle of the steering wheel.

ACTUATORS

M2351002000475

.

HYDRAULIC UNIT

As with the active skid control (ASC), ABS is con-
trolled by ASC-ECU.
NOTE: For more information on the internal hydraulic
circuit of hydraulic unit, refer to GROUP 35C

−

Sys-

tem Operation

P.35C-14

.

.

ABS WARNING LIGHT, ABS WARNING
DISPLAY, BRAKE WARNING LIGHT,
BRAKE WARNING DISPLAY

The ABS system illuminates or flashes the ABS
warning light, ABS warning display, brake warning
light, or brake warning display under the following
conditions, and informs the driver of the ABS system
status.

ABS warning light, ABS warning display, brake warning light and brake warning display illumination
or flashing pattern

NOTE:

.

•

*

: The ABS warning light and brake warning light

remain illuminated until the ignition switch is
turned to the LOCK (OFF) position.

•

When the brake fluid level in the brake fluid reser-
voir tank is at a specified value or less, or when
the parking brake lever is in the operating status,
the brake warning light illuminates.

AC709400

AB

Steering wheel sensor

State

ABS warning
light

ABS warning
display

Brake warning
light

Brake warning
display

Normal

Correct

−

−

−

−

Faulty

ABS failure

Illuminates

Illuminates

−

−

EBD failure

Illuminates

Illuminates

Illuminates

Illuminates

When scan
tool is
connected

Actuator not
operated

−

−

−

−

Actuator operated Flash (2Hz)

−

−

−

After actuator
operated

*

Illuminates

*

−

Illuminates

*

−