Mitsubishi Colt Ralliart. Manual — part 628

TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-57

STEP 5. 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. C1279 set?

YES :

Replace the ASC-ECU.

NO :

Intermittent malfunction (Refer to GROUP
00

− How to Cope with Intermittent

Malfunction

P.00-13

.)

Code No. C1340: Stop lamp switch signal error

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 determines that the brake is/is not applied

based on the signals from 2-system stop lamp switch
and pressure sensor (incorporated in ASC-ECU). If
the signals from 2-system stop lamp switch and pres-
sure sensor (incorporated in hydraulic unit) are differ,
the ECU determines that the trouble occurs and sets
the diagnosis code.

Stop Lamp 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

FUSIBLE
LINK

1

STOP
LAMP
SWITCH

ASC-ECU

Main

Index

Group

TOC

TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-58

DIAGNOSIS CODE SET CONDITIONS

If the signals from 2-system stop lamp switch and
pressure sensor (incorporated in hydraulic unit) are
differ, the ECU determines that the trouble occurs
and sets the diagnosis code.

Current trouble

• Damaged wiring harness and connectors

• Malfunction of the stop lamp switch

• 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 :

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. Connector check: B-27 Stop lamp switch
connector

Q: Is the check result normal?

YES :

Go to Step 3.

NO :

Repair the damaged connector.

STEP 3. Check of the stop lamp switch as single
unit
Refer to GROUP 35A

− Stop Lamp Switch Continuity

P.35A-22

.

Q: Is the check result normal?

YES :

Go to Step 4.

NO :

Replace the stop lamp switch.

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

Q: Is the check result normal?

YES :

Go to Step 5.

NO :

Repair the damaged connector.

STEP 5. Voltage measurement: A-05 ASC-ECU
connector

(1) Disconnect the connector, connect the ASC

check harness (Special tool: MB991984) to the
ABS-ECU side connector and harness-side
connector, and then measure the voltage at the
special tool connector side.

(2) Ignition switch: ON
(3) Measure the voltage between the terminal No. 6

and the body earth.

OK:

<When the brake pedal is not depressed>

2V or less

<When the brake pedal is depressed> 4.5V

or more

Q: Is the check result normal?

YES :

Go to Step 6.

NO :

Repair the wiring harness.

AC601083

Connector: A-05

AB

A-05(Black)

Harness side

AC601086AB

MB991984

ASC-ECU

Check connector

ASC-ECU harness connector

Main

Index

Group

TOC

TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-59

STEP 6. Measure the resistance at A-05 ASC-ECU
connector.

(1) Disconnect A-05 ASC-ECU 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 the terminal No.

23 and the body earth.

OK:

<When the brake pedal is not depressed>

Continuity (2V

Ω or less)

<When the brake pedal is depressed> No

continuity

Q: Is the check result normal?

YES : .

Go to Step 7.

NO :

Repair the wiring harness.

STEP 7. 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
(4) Depress the brake pedal for 2 seconds or more.

Q: Is the diagnosis code No. C1340 set?

YES :

Replace the ASC-ECU.

NO :

Intermittent malfunction (Refer to GROUP
00

− How to Cope with Intermittent

Malfunction

P.00-13

.)

AC601083

Connector: A-05

AB

A-05(Black)

Harness side

AC601085AG

MB991984

ASC-ECU

Check connector

ASC-ECU harness connector

Main

Index

Group

TOC

TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-60

Code No. C1345: Low brake fluid level

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 monitors the brake fluid level by the brake
fluid level switch signal.

DIAGNOSIS CODE SET CONDITIONS

When the brake fluid level is lower than the specified
value, the brake fluid level switch is turned ON, the
ASC-ECU terminal No. 32 is grounded, and then the
ECU determines that the brake fluid level is low and
sets this diagnosis code.

Current trouble

• Damaged wiring harness and connectors

• Low brake fluid level

• Long-time cornering in a certain direction (The

brake fluid level is tilted by centrifugal force, and
the low brake fluid level may be detected tempo-
rarily.)

• Brake fluid level switch malfunction

• 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 :

Go to Step 3.

NO :

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

− Troubleshooting

P.54D-13

.) On

completion, go to Step 2.

STEP2: Brake fluid level check
Check whether the brake fluid level is within the
specified value.

Q: Is the check result normal?

YES :

Go to Step 3.

NO :

Check the brake pad thickness and brake
fluid line leakage.

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