Mitsubishi Lancer Evolution VI. Manual - part 69

ABS  – 

Troubleshooting

35B-26

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.

D

Malfunction of combination meter

D

Malfunction of ABS-ECU

D

Malfunction of wiring harness (short circuit)

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

II

 is possible (where ABS-ECU power

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

NO

Check the harness wire, and repair if necessary.

D

Between ABS warning lamp and ABS-ECU

D

Between ABS warning lamp relay and valve relay

NO

D

Disconnect the ABS-ECU connector B-25.

D

Disconnect the valve relay connector A-76.

D

Ignition switch: ON

D

Does the ABS warning lamp go off?

YES

Replace the ABS-ECU.

Does the ABS warning lamp stay illuminated when the connector
B-52 is disconnected and the ignition switch is turned to ON?

YES

Replace the combination meter.

ABS  – 

Troubleshooting

35B-27

Inspection Procedure 5 <EVOLUTION-IV>

After the ignition key is turned to “ON”, the ABS warning
lamp blinks once, and when turned to “START”, it
illuminates. When returned to “ON”, the lamp flashes
once, and then switches off.

Probable cause

The ABS-ECU causes the ABS warning lamp to illuminate during the initial check.
During the initial check, the valve relay turns from off to on, off and back to on again.
If there is an open circuit in the harness between the ABS-ECU and the ABS warning
lamp, the lamp will illuminate only when the valve relay is OFF during valve relay
test, etc.

D

Malfunction of wiring harness or connector

D

Malfunction of ABS-ECU

OK

Check the trouble symptom.

NG

Check the harness between the com-
bination meter and the ABS-ECU, and
repair if necessary.

OK

Check the trouble symptom.

NG

Replace the ABS-ECU.

OK

Check the following connector:
B-25

NG

Repair

D

Disconnect valve relay connector
A-76.

D

Disconnect the ABS-ECU connec-
tor B-25.

D

Ignition switch: ON

D

Measure at the harness side of
ABS-ECU connector B-25.

D

Voltage between 44 and body
ground
OK: System voltage

NG

Check the following connector:
B-25

NG

Repair

Inspection Procedure 5 <EVOLUTION-V, VI>

After the ignition key is turned to “ON”, the ABS warning
lamp blinks once, and when turned to “START”, it
illuminates. When returned to “ON”, the lamp flashes
once, and then switches off.

Probable cause

The ABS-ECU causes the ABS warning lamp to illuminate during the initial check.
During the initial check, the valve relay turns from off to on, off and back to on again.
If there is an open circuit in the harness between the ABS-ECU and the ABS warning
lamp, the lamp will illuminate only when the valve relay is OFF during valve relay
test, etc.

D

Malfunction of wiring harness or connector

D

Malfunction of ABS-ECU

OK

Check the trouble symptom.

NG

Check the harness between the com-
bination meter and the ABS-ECU, and
repair if necessary.

OK

Check the trouble symptom.

NG

Replace the ABS-ECU.

OK

Check the following connector:
B-25

NG

Repair

Measure at ABS-ECU connector B-25.

D

Disconnect the connector  and
measure at the harness side.

D

Disconnect valve relay connector
A-76.

D

Ignition switch: ON

D

Voltage between 50 and body
ground
OK: System voltage

NG

Check the following connector:
B-25

NG

Repair

ABS  – 

Troubleshooting

35B-28

Inspection Procedure 6

When the ignition key is turned to “START”, the ABS
warning lamp does not illuminate.

Probable cause

The ABS-ECU is powered through IG2 which is turned off when the ignition key
is in START position. The ABS warning lamp is powered through IG1 which is not
turned off even when the ignition key is in START position. So the cause must be
a defective circuit on valve relay side.

D

Malfunction of valve relay

D

Malfunction of wiring harness or connector

OK

Check the trouble symptom.

NG

Check the harness between the com-
bination meter and valve relay, and
repair if necessary.

OK

Check the trouble symptom.

NG

Check the harness between the valve
relay and ground, and repair if neces-
sary.

OK

Check the following connector:
A-76

NG

Repair

OK

D

Disconnect the valve relay
connector A-76.

D

Disconnect ABS-ECU connector
B-25.

D

Ignition switch: ON

D

Measure at the harness side of
valve relay connector A-76.

D

Voltage between 3 and body
ground
OK: System voltage

NG

Check the following connectors
and diode:
A-76, B-26

NG

Repair

ABS valve relay check. 
(Refer to P.35B-39.)

NG

Replace the valve relay.

Inspection Procedure 7

Brake operation is abnormal.

Probable cause

The symptom varies depending on the driving conditions and the road surface conditions,
so problem diagnosis is difficult. However, if no diagnosis code is displayed, carry
out the following inspection.

D

Improper installation of wheel speed sensor

D

Malfunction of wiring harness or connector

D

Malfunction of wheel speed sensor

D

Malfunction of ABS rotor

D

Foreign material adhering to wheel speed sensor

D

Malfunction of wheel bearing

D

Malfunction of hydraulic unit

D

Malfunction of ABS-ECU

NG

Repair

Hydraulic unit check. (Refer to P.35B-37.)

OK

Wheel speed sensor circuit inspection. [Refer to Inspection Proce-
dure for “when either of diagnosis codes No. 11 to 14 is output”
(P.35B-7, 8).]

ABS  – 

Troubleshooting

35B-29

DATA LIST REFERENCE TABLE

The following items can be read by the MUT-

II

 from the ABS-ECU input data.

1.

When the system is normal

<EVOLUTION-IV>

Item No.

Check item

Checking requirements

Normal value

11

Front-right wheel speed sensor

Perform a test run

Vehicle speeds displayed on
the speedometer and MUT

II

12

Front-left wheel speed sensor

the speedometer and  MUT-

II

are identical.

13

Rear-right wheel speed sensor

14

Rear-left wheel speed sensor

16

System voltage

Ignition switch: ON

9 – 16 V

27

AYC monitor signal

Perform a test run.

Turns on and off alternately.

32

Acceleration sensor

Keep the vehicle stationary.

2.4 – 2.6 V

Drive the vehicle.

0.5 – 4.5 V

33

Stop lamp switch

Depress the brake pedal.

ON

Release the brake pedal.

OFF

<EVOLUTION-V, VI>

Item No.

Check item

Checking requirements

Normal value

11

Front-right wheel speed sensor

Perform a test run

Vehicle speeds displayed on
the speedometer and MUT

II

12

Front-left wheel speed sensor

the speedometer and  MUT-

II

are identical.

13

Rear-right wheel speed sensor

14

Rear-left wheel speed sensor

16

System voltage

Ignition switch: ON

9 – 16 V

32

Acceleration sensor 
(longitudinal)

Keep the vehicle stationary on level
ground.

2.4 – 2.6 V

Drive the vehicle.

0.5 – 4.5 V

33

Stop lamp switch

Depress the brake pedal.

ON

Release the brake pedal.

OFF

71

Acceleration sensor 
(lateral)

Keep the vehicle stationary on level
ground.

2.4 – 2.6 V

Drive the vehicle.

0.5 – 4.5 V

2.

When the ABS-ECU shut off ABS operation.

When the diagnosis system stops the ABS-ECU, the MUT-

II

 display data will be unreliable.