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Mitsubishi Pajero Pinin. Manual - part 255

ABS <4WD> –

Troubleshooting

35B-11

Inspection Procedure 4

Even after the engine is started, the ABS warning lamp
remains illuminated.

Probable cause

The cause is probably a short-circuit in the ABS warning lamp illumination circuit.

Malfunction of combination meter

Malfunction of ABS warning lamp relay

Malfunction of wiring harness (short circuit)

Malfunction of hydraulic unit and ABS-ECU

NOTE
This trouble symptom is limited to cases where communication with the MUT-

is possible (ABS-ECU

power supply is normal) and the diagnosis code is a normal diagnosis code.

Replace the hydraulic unit and ABS-ECU.

Repair

Check the harness wire, and repair if necessary.

Between ABS warning lamp relay and ABS-ECU

Check the trouble symp-
tom.

Measure at the ABS-ECU connector A-58.

Ignition switch: ON

Voltage between 22 and body earth
OK: System voltage

YES

Check the following connectors: A-58, A-57

ABS warning lamp relay check

Replace the ABS warning lamp relay.

Does the ABS warning lamp stay illuminated when the combination
meter connector C-07 is disconnected and the ignition switch
is turned to ON?

YES

Replace the combination meter.

Measure at the ABS warning lamp relay connector A-57.

Disconnect the connector, and measure at the harness side
connector.

Ignition switch: ON

Voltage between 5 and body earth
OK: System voltage

Does the ABS warning lamp stay illuminated when the ABS warning
lamp relay connector A-57 is disconnected and the ignition switch
is turned to ON?

Repair

Check the harness wire, and repair if necessary.

Between ignition switch and ABS warning lamp relay

Check the trouble symp-
tom.

Check the following connector: A-57

Check the harness wire, and repair if necessary.

Between combination meter and ABS warning lamp relay

ABS <4WD> –

Troubleshooting

35B-12

Inspection Procedure 5

Faulty ABS operation

Probable cause

This varies depending on the driving conditions and the road surface conditions,
so problem diagnosis is difficult. However, if a normal diagnosis code is displayed,
carry out the following inspection.

Improper installation of wheel speed sensor

Malfunction of wiring harness or connector

Malfunction of wheel speed sensor

Malfunction of ABS rotor

Foreign material adhering to wheel speed sensor

Malfunction of wheel bearing

Malfunction of hydraulic unit and ABS-ECU

Replace the hydraulic unit and ABS-ECU.

Check the trouble symptom.

Check the following connector: A-58

Measure at the ABS-ECU connector A-58.

Disconnect the connector, and measure at the harness side
connector.

Resistances between 26 and 27, 4 and 5, 24 and 23, 2 and
1
OK: 1.30 – 1.58 k

Ω

(The sensor harness and connector should be moved while
these inspections are carried out.)

Check the trouble symptom.

Check the following connectors:
A-58, C-25 <L.H. drive vehicles>, C-24 <R.H. drive vehicles>,
A-24, A-85, D-24, D-28

Repair

Wheel bearing check (Refer to GROUP 26 and GROUP 27 –
On-vehicle Service.)

Repair

ABS rotor check

Repair

Wheel speed sensor check

Replace the wheel speed sensor.

Wheel speed sensor output voltage check (Refer to P.35B-14.)

Hydraulic unit check

Wheel speed sensor installation check

Repair

Check the harness wire.

Between each wheel speed sensor and ABS-ECU

Repair

ABS <4WD> –

Troubleshooting

35B-13

CHECK AT ABS-ECU

TERMINAL VOLTAGE CHECK CHART

Measure the voltages between the respective terminal
and earth.

The terminal layout is shown in the illustration.

Terminal No.

Check item

Checking requirements

Normal condition

Stop lamp switch input

Ignition switch: ON

Stop lamp switch: ON

System voltage

Stop lamp switch: OFF

1 V or less

G sensor earth

Always

0 V

Input from G sensor

Ignition switch: ON

2.4 – 2.6 V

In ut from G sensor

Ignition switch: ON
Vehicle is horizontal

2.4 2.6 V

Solenoid valve power
supply

Always

System voltage

Diagnosis changeover
input

When the MUT-

is connected

0 V

input

When the MUT-

is not connected

Approx. 12 V

MUT-

When the MUT-

is connected

Serial communication
with MUT-

When the MUT-

is not connected

1 V or less

ABS warning lamp
relay transistor output

Ignition switch: ON

When the lamp is
switched off

2 V or less

When the lamp is illu-
minated

System voltage

ABS-ECU power
supply

Ignition switch: ON

System voltage

supply

Ignition switch: START

0 V

Motor power supply

Always

System voltage

RESISTANCE AND CONTINUITY BETWEEN
HARNESS-SIDE CONNECTOR TERMINALS

Turn the ignition key to the LOCK (OFF) position.

Disconnect the ABS-ECU connector.

Check the resistance and continuity between the terminals
indicated in the table below.

The terminal layout is shown in the illustration.

ABS <4WD> –

Troubleshooting/On-vehicle Service

35B-14

ABS-ECU terminal No.

Signal

Normal condition

1 – 2

Wheel speed sensor (rear left)

1.30 – 1.58 k

Ω

23 – 24

Wheel speed sensor (rear right)

4 – 5

Wheel speed sensor (front left)

26 – 27

Wheel speed sensor (front right)

11 – Body earth

Earth

Continuity

33 – Body earth

Earth

ON-VEHICLE SERVICE

WHEEL SPEED SENSOR OUTPUT VOLTAGE
CHECK

Lift up the vehicle and release the parking brake.

Disconnect the ABS-ECU connector.

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

Wheel speed
sensor

Front
left

Front
right

Rear left

Rear
right

Terminal No.

Output voltage

When measuring with a circuit tester:

42 mV or more

When measuring with an oscilloscope:

120 mV p-p or more

The followings are suspected if the output voltage is lower
than the value described above. Check the wheel speed
sensor, and replace if necessary.

Too large clearance between the pole piece of the
wheel speed sensor and ABS rotor

Faulty wheel speed sensor

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