Mitsubishi Colt Ralliart. Manual — part 625

TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-45

STEP 24. Diagnosis code recheck
Recheck if the diagnosis code is set.
(1) Erase the diagnosis code.
(2) Ignition switch: LOCK (OFF) position
(3) Ignition switch: ON

Q: Is the diagnosis code No. C1225 set?

YES : .

Intermittent malfunction (Refer to GROUP

00

− How to Cope with Intermittent

Malfunction

P.00-13

.)

NO : .

This diagnosis is complete.

Code No. C1226: Control solenoid valve (FR) pressure holding system

Code No. C1231: Control solenoid valve (FR) decompressing system

Code No. C1236: Control solenoid valve (FL) pressure holding system

Code No. C1241: Control solenoid valve (FL) pressure reducing system

Code No. C1246: Control solenoid valve (RR) pressure holding system

Code No. C1251: Control solenoid valve (RR) pressure reducing system

Code No. C1256: Control solenoid valve (RL) pressure holding system

Code No. C1261: Control solenoid valve (RL) decompressing system

Code No. C1300: Cut valve (FR/RL) <primary> system

Code No. C1305: Suction valve (FR/RL) <primary> system

Code No. C1310: Cut valve (FL/RR) <secondary> system

Code No. C1315: Suction valve (FL/RR) <secondary> system

CAUTION

If there is any problem in the CAN bus lines, an
incorrect diagnosis code may be set. Prior to this
diagnosis, always diagnose the CAN bus lines.

OPERATION

• ASC-ECU contains the power supply circuit (ter-

minal No. 44) for the solenoid valve, cut valve,
and suction valve. The solenoid valve, cut valve,
and suction valve are energised by the valve
relay, which is incorporated in ASC-ECU.

• The valve relay, which is incorporated in

ASC-ECU, is energising the solenoid valve, cut
valve, ad suction valve unless the initial check is
in progress when the ignition switch is turned on,
or the recurrent system check is in progress.

• ASC-ECU activates the solenoid valve by turning

on its driving transistor.

DIAGNOSIS CODE SET CONDITIONS

Code No. C1226, C1231, C1236, C1241, C1246,

C1251, C1256 and C1261.

• These codes are set when the ASC-ECU drive

signal does not match the feed back signal from
the solenoid valve.

Code No. C1300, C1305, C1310, and C1315

• These codes are set when an abnormality is

detected in ASC-ECU.

PROBABLE CAUSES

• Damaged wiring harness and connectors

• ASC-ECU malfunction

DIAGNOSTIC PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnostics
Use the M.U.T.-III to diagnose the CAN bus lines.

Q: Is the check result normal?

YES :

Replace the ASC-ECU.

NO :

Repair the CAN bus lines. (Refer to GROUP
54D, Troubleshooting

P.54D-13

.) On

completion, go to Step 2.

STEP 2. Diagnosis code recheck after resetting
CAN bus lines

Q: Are the diagnosis code C1226, C1231, C1236,

C1241, C1246, C1251, C1256, C1261, C1300, C1305,
C1310, and C1315 set?
YES :

Replace the ASC-ECU.

NO :

This diagnosis is complete.

Main

Index

Group

TOC

TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-46

Code No. C1266: Motor relay seizure

Code No. C1273: Motor relay stuck OFF

Code No. C1274: Motor relay stuck ON

CAUTION

If there is any problem in the CAN bus lines, an
incorrect diagnosis code may be set. Prior to this
diagnosis, always diagnose the CAN bus lines.

OPERATION

• ASC-ECU contains the power supply circuit (ter-

minal 45) for the pump motor. The pump motor is
energised by the motor relay, which is incorpo-
rated in ASC-ECU.

• The motor relay, which is incorporated in

ASC-ECU, is always off unless the motor sole-
noid valve check is activated when the vehicle is
started.

• ASC-ECU activates the pump motor by turning

on the ECU built-in motor relay when ABS or
ASC is working.

Hydraulic unit (Motor and Solenoid Valve) Circuit

Wire colour code
B : Black LG : Light green G : Green L : Blue W : White Y : Yellow SB : Sky blue
BR : Brown O : Orange GR : Grey R : Red P : Pink V : Violet PU : Purple

FUSIBLE
LINK

FUSIBLE
LINK

3

5

ASC-ECU

HYDRAULIC UNIT

SOLENOID
VALVE
POWER
SOURCE

ABS SOLENOID VALVE

MOTOR

MOTOR
POWER
SOURCE

Main

Index

Group

TOC

TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-47

DIAGNOSIS CODE SET CONDITIONS

These diagnostic trouble codes will be set under the
cases below.

Code No. C1266: Motor relay seizure

• The ABS-ECU monitors the voltage, which is cre-

ated by the pump motor coasting, after the motor
relay is turned off. If the voltage continues only for
too short period, the ECU determines that the
pump motor is not running smoothly (i.e. motor
seizure), and sets this diagnosis code.

Code No. C1273: Motor relay stuck OFF

• If the voltage, which is created by the pump

motor, is abnormal after the motor relay is turned
on, the ECU determines that the motor relay is
stuck off, and sets this diagnosis code.

Code No. C1274: Motor relay stuck ON

• If the voltage, which is created by the pump

motor, is abnormal after the motor relay is turned
off, the ECU determines that the motor relay is
stuck on, and sets this diagnosis code.

PROBABLE CAUSES

Current trouble

• Damaged wiring harness and connectors

• ASC-ECU malfunction

Past trouble

• Carry out diagnosis with particular emphasis on

connector(s) or wiring harness between the
power supply circuit (terminal 45) to the
ASC-ECU motor or earth circuit (terminal 46). For
diagnosis procedures, refer to How to treat past
trouble (GROUP 00

− How to Use Troubleshoot-

ing/Inspection Service Points

P.00-13

).

DIAGNOSTIC PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnostics
Use the M.U.T.-III to diagnose the CAN bus lines.

Q: Is the check result normal?

YES :

Go to Step 3.

NO :

Repair the CAN bus lines. (Refer to GROUP
54D

− Troubleshooting

P.54D-13

.) On

completion, go to Step 2.

STEP 2. Diagnosis code recheck after resetting
CAN bus lines

Q: Has diagnosis code C1266, C1273 or C1274 been

set?
YES :

Go to Step 3.

NO :

This diagnosis is complete.

STEP 3. Voltage measurement: A-05 ASC-ECU
connector

(1) Disconnect the connector, connect the ABS

check harness (Special tool: MB991984) to the
harness-side connector, and measure the voltage
at the special tool connector side.
NOTE: Do not connect the special tool to
ASC-ECU.

(2) Ignition switch: ON
(3) Measure the voltage between the terminal No. 45

and the body earth.

OK: Battery voltage

Q: Is the check result normal?

YES :

Go to Step 5.

NO :

Go to Step 4.

AC601083

Connector: A-05

AB

A-05(Black)

Harness side

AC601085AD

MB991984

ASC-ECU

Check connector

ASC-ECU harness connector

Main

Index

Group

TOC

TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-48

STEP 4. Connector check: A-05 ASC-ECU
connector

Q: Is the check result normal?

YES :

The open or short circuit may be present in

the power supply circuit to the motor. Repair
the harness wire between the ASC-ECU
connector terminal No. 45 and the fusible
link No. 3. Then go to Step 8.

NO :

Repair the connector, and then go to Step 8.

STEP 5. Measure the resistance at A-05 ASC-ECU
connector.

(1) Disconnect the connector, connect the ABS

check harness (Special tool: MB991984) to the
harness-side connector, and measure the voltage
at the special tool connector side.
NOTE: Do not connect the special tool to
ASC-ECU.

(2) Measure the resistance between terminal No. 46

and the body earth.

OK: Continuity exists (2

Ω or less)

Q: Is the check result normal?

YES :

Go to Step 7.

NO :

Go to Step 6.

AC601083

Connector: A-05

AB

A-05(Black)

Harness side

AC601083

Connector: A-05

AB

A-05(Black)

Harness side

AC601085AE

MB991984

ASC-ECU

Check connector

ASC-ECU harness connector

Main

Index

Group

TOC