Mitsubishi Colt Ralliart. Manual — part 637

TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-93

STEP 3. Check the parking brake switch as single
unit.
Refer to GROUP 36

− On-vehicle Service

P.36-5

.

Q: Is the check result normal?

YES :

Go to Step 4.

NO :

Replace the parking brake switch. (Refer to
GROUP 36

− Parking brake lever

P.36-7

.)

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) Pull the parking brake lever and turn the parking

brake switch to ON.

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

connector terminal No. 27 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. 27 and
C-44 parking brake switch connector
terminal No. 1.

STEP 5. Retest the system.

Q: Does the brake warning lamp illuminate when the

parking brake is operated?
YES :

Intermittent malfunction (Refer to GROUP

00

− How to Cope with Intermittent

Malfunction

P.00-13

.)

NO :

Replace the ASC-ECU.

STEP 6. Retest the system.

Q: Does the brake warning lamp illuminate when the

parking brake is operated?
YES :

Intermittent malfunction (Refer to GROUP

00

− How to Cope with Intermittent

Malfunction

P.00-13

.)

NO :

Replace the combination meter assembly,
and then go to Step 7.

STEP 7. Retest the system.

Q: Does the brake warning lamp illuminate when the

parking brake is operated?
YES :

This diagnosis is complete.

NO :

Replace the ASC-ECU.

AC601083

Connector: A-05

AB

A-05(Black)

Harness side

AC601085

AC601085AJ

MB991984

ASC-ECU

Check connector

ASC-ECU harness connector

Main

Index

Group

TOC

TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-94

Inspection Procedure 7: Brake warning lamp does not illuminate when the brake fluid level is low.
illuminates when the parking brake is operated.)

COMMENTS ON TROUBLE SYMPTOM

• When the brake fluid level is low, the ASC-ECU

sends the brake warning lamp drive signal to the
combination meter through the CAN communica-
tion lines.

• The ASC-ECU sends the lamp drive signal to the

combination meter during a bulb check (for three
seconds after the ignition switch is turned on)
through the CAN communication lines, and then
the combination meter activates the lamp.

• If the combination meter detects a ASC time-out

due to a failure in abnormal CAN communication,
the combination meter illuminates the lamp.

PROBABLE CAUSES

• Damaged wiring harness and connectors

• Brake fluid level switch malfunction

• Combination meter assembly malfunction

• ASC-ECU malfunction

DIAGNOSTIC PROCEDURE

STEP 1. M.U.T.-III data list
Using the data list, check that the brake fluid level
switch signal is normal.(Refer to

P.35C-109

.)

• Item No. 32: Brake fluid level switch

Q: Is the check result normal?

YES :

Go to Step 6.

NO :

Go to Step 2.

Brake Fluid Level Switch 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

ASC-ECU

BRAKE
FLUID
LEVEL
SWITCH

(EARTH 7)

Main

Index

Group

TOC

TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-95

STEP 2. Check A-03 brake fluid level switch
connector and A-05 ASC-ECU connector.

Q: Is the check result normal?

YES :

Go to Step 3.

NO :

Repair.

STEP 3. Check the brake fluid level switch as a
single unit.
Refer to GROUP 35A

− On-vehicle Service

P.35A-11

.

Q: Is the check result normal?

YES :

Go to Step 4.

NO :

Replace the reservoir assembly. (Refer to
GROUP 35A

− Master cylinder assembly

and brake booster

P.35A-23

.)

STEP 4. Measure the resistance at A-03 brake
fluid level switch connector and A-05 ASC-ECU
connector.

(1) Disconnect A-03 brake fluid level switch

connector and A-05 ASC-ECU connector.

(2) Make the brake fluid below the specified level,

and turn ON the brake fluid level switch.

(3) Measure the resistance between A-03 brake fluid

level switch connector terminal No. 2 and A-05
ASC-ECU connector terminal No. 32.

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-03
brake fluid level switch connector terminal
No. 2 and A-05 ASC-ECU connector
terminal No. 32.

AC601084

Connector: A-03

AD

A-03(Grey)

Harness
side

AC601083

Connector: A-05

AB

A-05(Black)

Harness side

AC601110

Connector: A-03, A-05

A-05
(Black)

A-03(Grey)

AB

A-03: Harness side

A-05: Harness side

Main

Index

Group

TOC

TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-96

STEP 5. Measure the resistance at A-03 brake
fluid level switch connector.

(1) Disconnect A-03 brake fluid level switch

connector.

(2) Measure the resistance between A-03 brake fluid

level switch connector terminal No. 2 and the
body earth.

OK: Continuity exists (2

Ω or less)

Q: Is the check result normal?

YES :

Go to Step 8.

NO :

Repair the harness wire between A-03
brake fluid level switch connector terminal
No. 2 and body earth.

STEP 6. Retest the system.

Q: Does the brake warning lamp illuminate when the

brake fluid level is low?
YES :

Intermittent malfunction (Refer to GROUP

00

− How to Cope with Intermittent

Malfunction

P.00-13

.)

NO :

Replace the combination meter assembly,
and then go to Step 7.

STEP 7. Retest the system.

Q: Does the brake warning lamp illuminate when the

brake fluid level is low?
YES :

This diagnosis is complete.

NO :

Replace the ASC-ECU.

STEP 8. Retest the system.

Q: Does the brake warning lamp illuminate when the

brake fluid level is low?
YES :

Intermittent malfunction (Refer to GROUP

00

− How to Cope with Intermittent

Malfunction

P.00-13

.)

NO :

Replace the ASC-ECU.

Inspection Procedure 8: Brake warning lamp does not extinguish when the ignition switch is ON.
(Always illuminates)

AC601084

Connector: A-03

AE

A-03(Grey)

Harness side

Brake Fluid Level Switch and Parking Brake Switch 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

ASC-ECU

BRAKE
FLUID
LEVEL
SWITCH

(EARTH 7)

PARKING
BRAKE
SWITCH

Main

Index

Group

TOC