Mitsubishi Lancer Evolution VI. Manual - part 71

ABS  – 

Troubleshooting

35B-34

Terminal No.

Normally

Signal name

38 – body ground

Solenoid valve IN (FR)

8.04 – 9.04 

Ω

39 – body ground

ECU ground

Conducting

45 – body ground

Solenoid valve IN (RL)

8.04 – 9.04 

Ω

46 – body ground

Solenoid valve OUT (FR)

4.04 – 4.54 

Ω

<EVOLUTION-V, VI>

Terminal No.

Signal name

Normally

1 – body ground

Solenoid valve OUT (FL) output

4.04 – 4.54 

Ω

2 – body ground

Solenoid valve OUT (RR) output

4.04 – 4.54 

Ω

3 – body ground

Solenoid valve IN (RR) output

8.04 – 9.04 

Ω

7 – 20

Wheel speed sensor (FL) input

1.4 – 1.8 k

Ω

8 – 21

Wheel speed sensor (RR) input

1.4 – 1.8 k

Ω

9 – 22

Wheel speed sensor (RL) input

1.4 – 1.8 k

Ω

10 – 23

Wheel speed sensor (FR) input

1.4 – 1.8 k

Ω

14 – body ground

Solenoid valve IN (FL) output

8.04 – 9.04 

Ω

15 – body ground

Ground

Conducting

25 – body ground

Ground

Conducting

40 – body ground

Solenoid valve OUT (RL) output

4.04 – 4.54 

Ω

41 – body ground

Solenoid valve OUT (FR) output

4.04 – 4.54 

Ω

42 – body ground

Ground

Conducting

48 – body ground

Valve relay monitor input

Conducting

49 – body ground

Motor relay monitor input

Conducting

51 – body ground

Solenoid valve IN (RL) output

8.04 – 9.04 

Ω

52 – body ground

Solenoid valve IN (FR) output

8.04 – 9.04 

Ω

ABS  – 

On-vehicle Service

35B-35

ON-VEHICLE SERVICE

WHEEL SPEED SENSOR OUTPUT VOLTAGE
CHECK

1.

Lift up the vehicle and release the parking brake.

2.

Disconnect the ABS-ECU connector, and then measure
the output voltage at the harness-side connector.

Caution
Insert the probe in the connector from the harness
side after releasing the double lock. Inserting it from
the terminal side could cause poor contacts.

3.

Rotate the wheel to be measured at approximately 1/2– 1
rotation per second, and check the output voltage using
a circuit tester (ACmV range) or an oscilloscope.

Terminal numbers

<EVOLUTION-IV>

Front left

Front right

Rear left

Rear right

6

8

9

7

19

21

22

20

<EVOLUTION-V, VI>

Front left

Front right

Rear left

Rear right

7

10

9

8

20

23

22

21

Output voltage

When measuring with a circuit tester:

70 mV or more

When measuring with an oscilloscope:

200 mV p-p or more

4.

If the output voltage is lower than the above values, the
following causes are suspected. Check the wheel speed
sensors and replace if necessary.

D

Too large gap between wheel speed sensor pole piece
and ABS rotor

D

Faulty wheel speed sensor

ABS-ECU connector (harness side)
<EVOLUTION-IV>

ABS-ECU connector (harness side)
<EVOLUTION-V, VI>

ABS  – 

On-vehicle Service

35B-36

Inspecting Waveforms with an Oscilloscope

Use the following method to observe the output voltage
waveform from each wheel sensor with an oscilloscope.
Check the connection of the sensor harness and connector
before using the oscilloscope.
Start the engine, and rotate the wheels by engaging 1st gear.

NOTE
(1) The waveform measurements can also be taken while

the vehicle is actually moving.

(2) The output voltage will be small when the wheel speed

is low, and similarly it will be large when the wheel speed
is high.

Points in Waveform Measurement

Symptom

Probable causes

Remedy

Too small or zero waveform
amplitude

Faulty wheel speed sensor

Replace sensor

Waveform amplitude fluctuates
excessively (this is no problem if

Axle hub eccentric or with large runout

Replace hub

c

y (t

p

the minimum amplitude is 100 mV
or more)

Faulty ABS-ECU ground

Repair

Noisy or disturbed waveform

Open circuit in sensor

Replace sensor

Open circuit in harness

Correct harness

Incorrectly mounted wheel speed sensor

Mount correctly

ABS rotor with missing or damaged teeth

Replace rotor

Caution
The wheel speed sensor cable moves following motion of the front or rear suspension. Therefore,
it is likely that it has an open circuit only when driving on rough roads and it functions normally
on ordinary roads. It is, therefore, recommended to observe sensor output voltage waveform also
under special conditions, such as rough road driving.

When turning by hand

When idling (5 – 6 km/h),
1st gear

10.0 ms/DIV 1 V/DIV

ABS  – 

On-vehicle Service

35B-37

HYDRAULIC UNIT CHECK

Caution
Turn the ignition switch off before connecting or disconnecting the MUT-

II

.

1.

Jack up the vehicle and support the vehicle with rigid racks placed at the specified jack-up points
or place the wheels which are checked on the rollers of the braking force tester.

Caution
(1) The roller of the braking force tester and the tyre should be dry during testing.
(2) When testing the front brakes, apply the parking brake, and when testing the rear brakes,

stop the front wheels by chocking them.

2.

Turn the ignition key to the OFF position and set the MUT-

II

.

3.

After checking that the shift lever is in neutral, start the engine.

NOTE
(1) During the actuator test, the ABS warning lamp will illuminate and the anti-skid control will be

cancelled.

(2) When the ABS has been interrupted by the fail-safe function, the MUT-

II

 actuator testing cannot

be used.

4.

Use the MUT-

II

 to force-drive the actuator.

5.

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 decreases when the actuator is force-driven.

Front wheel

785 – 981 N

Rear wheel

294 – 490 N

The result should be as shown in the following diagram.

Pedal operation

Depressed

Released

Solenoid valve 
position

Increase in pressure

Steady pressure

Reduction in pressure

Checking the 
brake force

Lock

Drag force when the pedal is free

MUT-

II

 actuator test

(Item No. 01, 02, 03, 04) start

1 seconds

2 seconds

about 0.05 seconds