Mitsubishi Grandis. Manual — part 897

GENERAL INFORMATION

ANTI-SKID BRAKING SYSTEM (ABS)

35B-3

GENERAL INFORMATION

M1352000100603

FEATURES

The 4ABS ensures directional stability and
controllability during hard braking.
For vehicles with this type of ABS, 4 sensors (4
channels) are installed on front and rear wheels
allowing independent left and right control.
The system has the following features:
NOTE: On vehicles with ASC, the ABS system is
controlled by the TCL/ASC-ECU. For the system
construction, refer to GROUP 35C, General
Information

P.35C-3

.

• EBD (Electronic Brake-force Distribution system)

control has been added to provide the ideal
braking force for the rear wheels.

• Magnetic encoder for detecting wheel speed has

been installed as a wheel speed sensor instead
of the rotor.

• For wiring harness saving and secure data

communication, CAN

*

bus has been adopted as

a tool of communication with another ECU.

NOTE:

*

: For more information about CAN

(Controller Area Network), refer to GROUP 54D

P.54D-9

.

EBD CONTROL

In ABS, electronic control is used so the rear wheel
brake hydraulic pressure during braking is regulated
by rear wheel control solenoid valves in accordance
with the vehicle's rate of deceleration, and the front
and rear wheel slippage which are calculated from
the signals received from the various ABS sensors.
EBD control is a control system which provides a
high level of control for both vehicle braking force
and vehicle stability. The system has the following
features:

• Because the system provides the optimum rear

wheel braking force regardless of vehicle load
conditions and the condition of the road surface,
the system reduces the required pedal
depression force, particularly when the vehicle is
heavily loaded or driven on road surfaces with
high frictional coefficients.

• Because the duty placed on the front brakes is

reduced, the increases in pad temperature can
be controlled during brakes application to
improve the wear resistance characteristics of the
pad.

• Control valves such as the proportioning valve

are no required.

SPECIFICATIONS

Item

Specification

ABS control method

4-sensor, 4-channel

No.of rotor teeth

Front

96 (N pole:48 S pole:48)

Rear

86 (N pole:43 S pole:43)

Wheel speed sensor

Type

Semiconductor

SERVICE SPECIFICATIONS

ANTI-SKID BRAKING SYSTEM (ABS)

35B-4

CONSTRUCTION DIAGRAM

SERVICE SPECIFICATIONS

M1352000300696

AC311861AC

ABS warning
lamp

Hydraulic unit and
ABS-ECU

Diagnosis connector

Stop lamp switch

Wheel speed sensor (front)

Wheel speed rotor (rear)

Brake warning
lamp

Item

Standard value

Wheel speed sensor current mA

5.9

− 8.4

Wheel speed sensor insulation resistance M

Ω

5

− 100

SPECIAL TOOLS

ANTI-SKID BRAKING SYSTEM (ABS)

35B-5

SPECIAL TOOLS

M1352000600824

TROUBLESHOOTING

STANDARD FLOW OF DIAGNOSTIC
TROUBLESHOOTING

M1352011100663

Refer to GROUP 00, How to Use

Troubleshooting/Inspection Service Points

P.00-5

.

Tool

Number

Name

Use

MB991955
A: MB991824
B: MB991827
C: MB991910
D: MB991911
E: MB991825
F: MB991826

MUT-III sub-assembly
A: Vehicle
Communication Interface
(V.C.I.)
B: MUT-III USB cable
C: MUT-III main harness
A (Vehicles with CAN
communication system)
D: MUT-III main harness
B (Vehicles without CAN
communication system)
E: MUT-III measurement
adapter
F: MUT-III trigger harness

Checking the ABS

CAUTION

MUT-III main harness A
(MB991911) should be
used. MUT-III main
harness B should not
be used for this vehicle.

MB991974

ABC check harness

Checking the ABS-ECU

MB991910

MB991826

MB991955

MB991911

MB991824

MB991827

MB991825

A

B

C

D

E

F

DO NOT USED

B991974

TROUBLESHOOTING

ANTI-SKID BRAKING SYSTEM (ABS)

35B-6

NOTES WITH REGARD TO DIAGNOSIS

M1352012600218

1. The ABS is a system which controls the brake

pressure by means of the operation of the ECU.
Accordingly, the following symptoms may occur at
times, but these are a sign of normal ABS
operation, and do not indicate a malfunction.

2. For road surfaces such as snow-covered roads

and gravel roads, the braking distance for
vehicles with ABS can sometimes be longer than
that for other vehicles. Accordingly, advise the
customer to drive safely on such roads by
lowering the vehicle speed and not being too
overconfident.

3. Diagnosis detection condition can vary depending

on the diagnosis code. Make sure that checking
requirements listed in the "Comment" are satisfied
when checking the trouble symptom again.

Phenomenon

Explanation of phenomenon

When the engine starts, a knocking sound can be heard coming
from the engine compartment.

This sound occurs as a result of system
operation checking, and is not a
malfunction.

• Sound of the motor inside the ABS hydraulic unit operation.

(whine)

• Sound is the generated along with vibration of the brake

pedal. (scraping)

• When ABS operates, sound is generated from the vehicle

chassis due to repeated brake application and release.
(Thump: suspension; squeak: tyres)

This is the sound of normal system
operation, and is not a malfunction.

Shocks are felt if the brake pedal is depressed when driving at
low speed.

This is due to system operation checking
(starting-of check when the vehicle speed
reaches a certain number of km/h) and is
not a malfunction.