Mitsubishi Galant (2004+). Manual - part 540

ON-VEHICLE SERVICE

TSB Revision

ANTI-LOCK BRAKING SYSTEM (ABS)

35B-105

3. Manually turn the wheel to be measured 1/2 to 1

turn/second. Measure the output voltage with a voltmeter or
oscilloscope.
NOTE: Check the connection of the sensor harness and
connector before using the oscilloscope.

Output voltage:

• Minimal voltmeter reading: 42 mV

• Maximum voltmeter reading: 300 mV

• Minimal oscilloscope reading: 120 mV

• Maximum oscilloscope reading: 600 mV

Probable causes of low output voltage

• Wheel speed sensor pole piece-to-wheel speed rotor clear-

ance too large

• Faulty wheel speed sensor

4. To observe the waveform with an oscilloscope:

• Front Wheels: Shift into "D" range and drive the wheels.

• Rear Wheels: Turn the wheels manually at a constant

speed

NOTE: The output waveform is low when the wheel speed is
low. Similarly, it will be higher as the wheel speed increases.
Waveform may also be observed by driving the vehicle.

POINTS IN WAVEFORM MEASUREMENT

NOTE: The wheel speed sensor cable moves in relation to motion of the front or rear suspension. Therefore,
it is likely that it has an open circuit only when driving on rough roads but it functions normally when driving on
smooth roads. It is recommended to observe sensor output voltage waveform also under special conditions,
such as driving on a rough road.

AC000949 AC

WHEN TURNED MANUALLY

IN "D" RANGE, IDLING
[5

− 6 km/h (3 − 4 mph)]

[10.0 ms/DIV 1 V/DIV]

SYMPTOM

PROBABLE CAUSE

REMEDY

Too small or zero waveform
amplitude

Faulty wheel speed sensor or
excessive gap between it and the
wheel speed rotor

Replace wheel speed sensor

Waveform amplitude fluctuates
excessively (This is no problem if
the minimum amplitude is 100 mV
or more)

Axle hub eccentric or with large
runout

Replace hub assembly

Faulty ABS-ECU ground

Repair harness wires

Noisy or disturbed waveform

Open circuit in wheel speed sensor Replace wheel speed sensor
Open circuit in harness

Repair harness wire

Incorrectly mounted wheel speed
sensor

Mount wheel speed sensor
correctly

Wheel speed rotor with missing or
damaged teeth

Replace wheel speed rotor

ON-VEHICLE SERVICE

TSB Revision

ANTI-LOCK BRAKING SYSTEM (ABS)

35B-106

HYDRAULIC UNIT CHECK

M1352001700512

Required Special Tools:

• MB991958: MUT-III Sub Assembly

• MB991824: Vehicle Communication Interface (V.C.I.)

• MB991827: MUT-III USB Cable

• MB991910: MUT-III Main Harness A (Vehicles with CAN

communication system)

CAUTION

• The roller of the braking force tester and the tire should

be dry during testing.

• When testing the front brakes, apply the parking brake.

When testing the rear brakes, stop the front wheels
with chocks.

1. Jack up the vehicle. Then support the vehicle with rigid

racks at the specified jack-up points or place the front or rear
wheels on the rollers of the braking force tester.

2. Release the parking brake, and feel the drag force (drag

torque) on each road wheel. When using the braking force
tester, take a reading of the brake drag force.

CAUTION

To prevent damage to scan tool MB991958, always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
3. Connect scan tool MB991958 to the data link connector.
4. After checking that the selector lever is in "P" range, start the

engine.

5. Select "Interactive Diagnosis" from the start-up screen.
6. Select "System Select."
7. Choose "ABS" from the "CHASSIS" tab.
8. Select "Actuator Test" from "ABS" screen
9. Choose an appropriate item for hydraulic unit check.

NOTE: The ABS system will switch to the scan tool mode
and the ABS warning light will illuminate.
NOTE: When the ABS has been interrupted by the fail-safe
function, scan tool MB991958 actuator testing cannot be
used.

AC305412

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

ON-VEHICLE SERVICE

TSB Revision

ANTI-LOCK BRAKING SYSTEM (ABS)

35B-107

10.Turn the wheel by hand and check the change in braking

force when the brake pedal is depressed. When using the
braking force tester, depress the brake pedal until the
braking force is at the following values, and check that the
braking force changes to the brake drag force reading taken
in step 2 when the actuator is force-driven. The result should
be as shown in the diagram above.

Front wheel

785

− 981 N (176 − 220 lb.)

Rear wheel

588

− 784 N (132 − 176 lb.)

AC000954AB

SCAN TOOL ACTUATOR TEST
(ITEM NO.01, 02, 03, 04) START

1 s

2 s

3 s

DEPRESSED

RELEASED

PRESSURE INCREASE

PRESSURE DECREASE

PRESSURE HOLD

LOCK

DRAG FORCE
WHEN THE
PEDAL IS FREE

PEDAL
OPERATION

SOLENOID
VALVE
POSITION

CHECKING
THE BRAKE
FORCE

ON-VEHICLE SERVICE

TSB Revision

ANTI-LOCK BRAKING SYSTEM (ABS)

35B-108

11.If the result of inspection is abnormal, repair according to the

Diagnosis Table below.

12.After inspection, disconnect scan tool MB991958

immediately after turning the ignition switch to the "LOCK"
(OFF) position.

IN THE EVENT OF A DISCHARGED BATTERY

M1352003500547

WARNING

If the ABS is not operating, the vehicle will be unsta-
ble during braking, Do not drive the vehicle with the
ABS-ECU connector disconnected or with the ABS
not operating.

If the engine is started using a booster cable when the battery
is completely flat, and the vehicle is then driven without waiting
for the battery to be recharged, the engine may misfire and it
may not be possible to drive the vehicle. This is because the
ABS consumes a large amount of current when carrying out its
initial checks. If this happens, recharge the battery fully.

DIAGNOSIS TABLE

MUT-III
DISPLAY

OPERATION

INSPECTION
RESULT

JUDGMENT PROBABLE

CAUSE

REMEDY

01 FR VALVE
02 FL VALVE
03 RR VALVE
04 RL VALVE

• Depress brake

pedal to lock
wheel.

• Using scan tool

MB991958, select
the wheel to be
checked and force
the actuator to
operate.

• Turn the selected

wheel manually to
check the change
of brake force.

Brake force is
released for
three seconds
after wheels
have been
locked.

Normal

−

Wheel does not
lock when brake
pedal is
depressed.

Abnormal

Clogged brake
line other than
hydraulic unit

Check and clean
brake line

Clogged
hydraulic circuit
in hydraulic unit

Replace
hydraulic unit
assembly

Brake force is
not released

Abnormal

Incorrect
hydraulic unit
brake tube
connection

Connect correctly

Hydraulic unit
solenoid valve
not functioning
correctly

Replace
hydraulic unit
assembly

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