Mitsubishi Evolution X. Manual — part 750

DIAGNOSIS

TSB Revision

ACTIVE SKID CONTROL SYSTEM (ASC)

35C-7

PRECAUTIONS FOR DIAGNOSIS

M1355009500113

1. ASC controls the brake pressure by the assistance of ECU.

The symptoms described in the table below may occur
during the normal ASC operation. However, they do not
indicate any sign of malfunction.

2. On snowy or gravel roads, a vehicle with ABS sometimes

requires a longer braking distance compared to the one
without ABS. Considering this characteristics, advise the
customer to drive the vehicle safely at lower speed and not
to place too much confidence on the ABS system when
driving on such roads.

3. The detection conditions of diagnostic trouble code differ

with each diagnostic trouble code. When the trouble
symptoms are rechecked, conditions described in the
description for the diagnostic trouble code procedures must
be satisfied.

ABS WARNING LIGHT AND BRAKE WARNING
LIGHT INSPECTION

M1352012000670

Check if the ABS warning light and brake warning light is illumi-
nated as follows.
NOTE: The brake warning light is used as the warning lights for
the parking brake, brake fluid level, and EBD control.

Symptoms

Description of symptoms

• When ASC operates, the operating noise is generated from

the motor integrated in the hydraulic unit. (Screech)

• Noise is generated from the brake pedal together with the

vibration. (Boom, boom)

• When ASC operates, the system repeats the activation and

deactivation. At this time, the noise is generated from the
chassis components. (Clunk: Suspension; Squeak: Tire)

These noises are generated when the
system and brake pedal operate
normally, and they do not indicate any
sign of malfunction.

• A slight shock is felt occasionally when the brake pedal is

depressed lightly during the low speed driving.

• Small clicking noise is heard occasionally from the engine

compartment.

This noise is generated when the system
operation check <startup check
performed when the vehicle speed is at
few km/h (mile)> is performed, and it
does not indicate any malfunction.

DIAGNOSIS

TSB Revision

ACTIVE SKID CONTROL SYSTEM (ASC)

35C-8

1. When the ignition switch is turned to the ON position, the

ABS warning light and brake warning light illuminate.

2. After an illumination for approximately 3 seconds

*1

, the ABS

warning light and brake warning light will be turned off

*2

.

3. Other than the above, the system may have a malfunction.

Check the diagnostic trouble code.

NOTE:

.

•

*1

: ABS warning light may remain illuminated until the vehi-

cle speed reaches approximately 10 km/h. Only when a
diagnostic trouble code relating to the wheel speed sensor
malfunction or pump motor malfunction is stored in
ASC-ECU as a past trouble, ASC-ECU keeps the ABS
warning light illuminated until it can verify (at startup check)
that the malfunction for that code is resolved.

•

*2

: The brake warning light does not turn off when the park-

ing brake is applied or the brake fluid level is low.

DIAGNOSTIC FUNCTION

M1355001000147

ASC-ECU has the following functions for easier sys-
tem checks. All the following items can be diagnosed
using the scan tool.

• Diagnostic trouble code set (Refer to

P.35C-20

.)

• Service data output (Refer to

P.35C-255

.)

• Actuator test (Refer to

P.35C-257

.)

FAIL-SAFE FUNCTIONS

When a malfunction is determined by the diagnostic
function, ASC-ECU illuminates the ABS warning
light, ABS warning display, brake warning display,
brake warning light

*

, ASC warning display, and ASC

OFF display. At the same time, ASC-ECU prohibits
the ABS, EBD, skid control, and TCL control.

NOTE:

*

: The brake warning light and brake warning

display are used as the EBD control warning light.

.

AC610579AB

ABS warning light

ON
ACC,
LOCK

START

Brake warning light

ABS warning
light and
brake warning
light

Ignition
switch

Illuminate

Off

Approximately 3s

DIAGNOSIS

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ACTIVE SKID CONTROL SYSTEM (ASC)

35C-9

Illumination condition of warning light and display in case of failure

DTC
No.

Item

Brake
warning light,
brake warning
display

ABS warning
light, ABS
warning
display

ASC warning
display

ASC OFF light

C100A Abnormality in FL wheel speed

sensor circuit

Extinguished

*1

Illuminated

*2

Illuminated

Illuminated

C1015 Abnormality in FR wheel speed

sensor circuit

C1020 Abnormality in RL wheel speed

sensor circuit

C102B Abnormality in RR wheel speed

sensor circuit

C1011 Abnormality in FL wheel speed

sensor signal

Extinguished

*1

Illuminated

*2

Illuminated

Illuminated

C101C Abnormality in FR wheel speed

sensor signal

C1027 Abnormality in RL wheel speed

sensor signal

C1032 Abnormality in RR wheel speed

sensor signal

C1014 Mutual monitoring of FL wheel

speed sensor

Extinguished

*1

Illuminated

*2

Illuminated

Illuminated

C101F Mutual monitoring of FR wheel

speed sensor

C102A Mutual monitoring of RL wheel

speed sensor

C1035 Mutual monitoring of RR wheel

speed sensor

C1041 Abnormality in periodical signal

for FL wheel speed sensor

Extinguished

*1

Illuminated

*2

Illuminated

Illuminated

C1042 Abnormality in periodical signal

for FR wheel speed sensor

C1043 Abnormality in periodical signal

for RL wheel speed sensor

C1044 Abnormality in periodical signal

for RR wheel speed sensor

C1046 FL wheel speed sensor control

phase time exceeded

Extinguished

*1

Illuminated

*2

Illuminated

Illuminated

C1047 FR wheel speed sensor control

phase time exceeded

C1048 RL wheel speed sensor control

phase time exceeded

C1049 RR wheel speed sensor control

phase time exceeded

DIAGNOSIS

TSB Revision

ACTIVE SKID CONTROL SYSTEM (ASC)

35C-10

C104B Abnormality in FL wheel inlet

valve system

Illuminated

Illuminated

Illuminated

Illuminated

C104F Abnormality in FR wheel inlet

valve system

C1053 Abnormality in RL wheel inlet

valve system

C1057 Abnormality in RR wheel inlet

valve system

C105F Abnormality in FL wheel outlet

valve system

Illuminated

Illuminated

Illuminated

Illuminated

C1063 Abnormality in FR wheel outlet

valve system

C1067 Abnormality in RL wheel outlet

valve system

C105B Abnormality in RR wheel outlet

valve system

C1200 Abnormality in FL/RR wheel cut

valve system

Illuminated

Illuminated

Illuminated

Illuminated

C1204 Abnormality in FR/RL wheel cut

valve system

C1208 Abnormality in FL/RR wheel

suction valve system

C120C Abnormality in FR/RL wheel

suction valve system

C2104 Faulty valve power supply circuit Illuminated

Illuminated

Illuminated

Illuminated

C1073 Faulty motor drive circuit

Extinguished

Illuminated

*2

Illuminated

Illuminated

C2116 Abnormality in power supply

voltage in pump motor

Extinguished

Illuminated

*2

Illuminated

Illuminated

C121D Abnormality in brake fluid

pressure sensor circuit

Extinguished

Illuminated

Illuminated

Illuminated

C121E Abnormality in brake fluid

pressure sensor output signal

Extinguished

Illuminated

Illuminated

Illuminated

C2000 Abnormality in wheel fluid

pressure sensor circuit

Extinguished

Illuminated

Illuminated

Illuminated

C2001 Abnormality in wheel fluid

pressure sensor output signal

Extinguished

Illuminated

Illuminated

Illuminated

C1000 Abnormality in stoplight switch

circuit

Extinguished

Extinguished

Illuminated

Illuminated

C123B Prolonged operation of ASC

Extinguished

Extinguished

Illuminated

Illuminated

C2200 Abnormality in ASC-ECU

Illuminated

*3

Illuminated

*3

Illuminated

Illuminated

DTC
No.

Item

Brake
warning light,
brake warning
display

ABS warning
light, ABS
warning
display

ASC warning
display

ASC OFF light