Mitsubishi Colt Ralliart. Manual — part 635

TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-85

TROUBLE SYMPTOM CHART

M1357001000013

CAUTION

During diagnosis, a diagnosis code associated with other system may be set when the ignition switch
is turned on with connector(s) disconnected. On completion, check if the diagnosis code is set. If the
diagnosis code has been set, erase that code.

SYMPTOM PROCEDURES

Inspection Procedure 1: Cannot communicate with ASC-ECU using the M.U.T.-III

COMMENTS ON TROUBLE SYMPTOM

If the M.U.T.-III cannot communicate with the
ASC-ECU, the CAN bus lines may be defective.
When malfunction occurs in the ASC-ECU power
supply circuit and earth circuit, the CAN bus diagno-
sis detects the abnormality. This symptom also
appears when an incorrect vehicle model is selected
on the M.U.T.-III.

PROBABLE CAUSES

• Damaged wiring harness and connectors

• ASC-ECU malfunction

DIAGNOSTIC PROCEDURE

STEP 1. M.U.T.-III selected vehicle model
confirmation
Confirm which vehicle model is selected on the
M.U.T.-III vehicle information screen.

Q: Is the correct vehicle model selected?

YES :

Go to Step 2.

NO :

Input the vehicle information correctly.

STEP 2. 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

.)

Trouble symptom

Inspection
procedure
number

Reference page

Cannot communicate with ASC-ECU using the M.U.T.-III

1

P.35C-85

ASC-ECU power supply circuit system

2

P.35C-86

The ABS warning lamp and the ASC indicator lamp don't illuminate when
the ignition switch is turned ON.

3

P.35C-89

ABS warning lamp and ASC indicator lamp does not extinguish after the
engine is started.

4

P.35C-90

Brake warning lamp does not illuminate at all.

5

P.35C-91

Brake warning lamp does not illuminate when the parking brake is
operated. (illuminates when the bulb check is performed.)

6

P.35C-92

Brake warning lamp does not illuminate when the brake fluid level is low
(illuminates when the parking brake is operated).

7

P.35C-94

Brake warning lamp does not extinguish when the ignition switch is ON
(remains illuminated).

8

P.35C-96

Stability control system operates too frequently (no diagnosis code is set). 9

P.35C-100

Steering wheel sensor power supply system

10

P.35C-102

G and yaw rate sensor power supply circuit

11

P.35C-105

Main

Index

Group

TOC

TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-86

Inspection Procedure 2: ASC-ECU power supply circuit malfunction

OPERATION

• The ASC-ECU is energised by the ignition switch

(IG1) through multi-purpose fuse 40 and the
ASC-ECU terminal No. 40.

• When malfunction occurs in ASC-ECU power

supply, the communication with M.U.T.-III
becomes unavailable.

PROBABLE CAUSES

• Damaged wiring harness and connectors

• Battery failure

• Charging system failed

• ASC-ECU malfunction

DIAGNOSTIC PROCEDURE

STEP 1. Battery terminal voltage measurement
(1) Ignition switch: ON
(2) Engine: Started
(3) Measure the voltage between the battery

terminals.

OK: 10V or more

Q: Is the check result normal?

YES :

Go to Step 2.

NO :

Diagnose the charging system. (Refer to
GROUP 16

− On-vehicle Service

P.16-6

.)

ASC-ECU Power Source 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

IGNITION
SWITCH (IG1)

ASC-ECU

Main

Index

Group

TOC

TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-87

STEP 2. Connector check: A-05 ASC-ECU
connector

Q: Is the check result normal?

YES :

Go to Step 3.

NO :

Repair the damaged connector.

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

(1) Disconnect A-05 ASC-ECU connector, and

connect the ABS check harness (Special tool:
MB991984) to the ASC-ECU side connector and
the harness side connector.

(2) Ignition switch: ON
(3) Engine: Started
(4) Measure the voltage between the ABS check

harness (Special tool: MB991984) connector
terminal No. 40 and the body earth.

OK: 10 V or more

Q: Is the check result normal?

YES :

Go to Step 4.

NO :

Repair the harness wire between A-05
ASC-ECU connector terminal No. 40 and
the ignition switch (IG1).

AC601083

Connector: A-05

AB

A-05(Black)

Harness side

AC601083

Connector: A-05

AB

A-05(Black)

Harness side

AC601086AD

MB991984

ASC-ECU

Check connector

ASC-ECU harness connector

Main

Index

Group

TOC

TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-88

STEP 4. Measure the resistance at A-05 ASC-ECU
connector.

(1) Disconnect the A-05 ASC-ECU connector, and

connect the ABS check harness (Special tool:
MB991984) to the harness side connector.
NOTE: . Do not connect the ABS check harness
(Special tool: MB991984) to the ASC-ECU.

(2) Measure the resistance between A-05 ASC-ECU

connector terminal No. 43 and the body earth.

OK: Continuity exists (2

Ω or less)

Q: Is the check result normal?

YES : .

Go to Step 5.

NO : .

Repair the harness wire between A-05

ASC-ECU connector terminal No. 43 and
the body earth.

STEP 5. Retest the system.

Q: Can the ASC-ECU communicate with the M.U.T.-III?

YES :

Intermittent malfunction (Refer to GROUP

00

− How to Cope with Intermittent

Malfunction

P.00-13

.)

NO :

Replace the ASC-ECU.

AC601083

Connector: A-05

AB

A-05(Black)

Harness side

AC601085AI

MB991984

ASC-ECU

Check connector

ASC-ECU harness connector

Main

Index

Group

TOC