Mitsubishi L200. Manual - part 468

TROUBLESHOOTING

ACTIVE STABILITY & TRACTION CONTROL SYSTEM (ASTC)

35C-128

Inspection Procedure 7: The ASTC system cannot be disabled when ASC OFF switch is pressed to 
turn the system OFF.

ASC Switch Circuit

ASC OFF 
SWITCH

COMBINATION 
METER

ILLUMINATION 
CONTROL CIRCUIT

TAIL LAMP 
RELAY

ETACS-ECU

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

ASTC-ECU

NOTE

: RHD
:

NOTE

: RHD
: LHD

COMBINATION 
METER

19

14

13

1

3

15

2

16

4

18

6

17

5

7

22

10

21

20

8 9

23

11

24

12

ACB00858

AC800980

AG

Connector: A-48

(B)

AC600688

Connector: C-13 <LHD>

BS

AC600687CR

Connectors: C-54, C-137, C-138 <LHD>

C-54

C-54

2

1

3

13

12

14

21

10

5

4

6

16

15

17

7 8 9

19

18

20

11

22

C-137, C-138

C-137, C-138

AC600623DK

Connector: C-13, C-14, C-137, C-138 <RHD>

C-13

C-14

C-14

C-13

2

1

3

13

12

14

21

10

5

4

6

16

15

17

7 8 9

19

18

20

11

22

C-137, C-138

C-137, C-138

AC600687CS

Connector: C-113, C-140 <LHD>

C-113 Harness side

18

19

21

22

20

2423

11

12

10 9

7

8

6

1413

171615

3

4

5

1

2

 C-140 Harness side 

1

5

6

4 3 2

AC600623

C-113

C-140

CX

Connectors: C-113, C-140 <RHD>

C-113 

Harness side

C-140 Harness side 

1

5

6

4 3 2

TROUBLESHOOTING

ACTIVE STABILITY & TRACTION CONTROL SYSTEM (ASTC)

35C-129

OPERATION
ASTC-ECU terminal No.29 is earthed every time the 
ASC OFF switch is pressed. ASTC-ECU monitors 
this operation state and turns the ASC and ATC sys-
tem ON or OFF.

COMMENT
The cause is probably an open-circuit in the ASC 
OFF switch circuit.

PROBABLE CAUSES

• Malfunction of the ASC OFF switch

• Damaged harness, connector

• Malfunction of the hydraulic unit assembly (inte-

grated with ASTC-ECU)

DIAGNOSIS PROCEDURE

STEP 1. Connector check: A-48 ASTC-ECU 
connector, C-13 intermediate connector, C-14 
intermediate connector <RHD>, C-54 
intermediate connector <LHD>, C-113 
combination meter connector, C-137 joint 
connector, C-138 joint connector, C-140 ASC OFF 
switch connector

Q: Is the check result normal?

YES : 

Go to Step 2.

NO : 

Repair or replace it. Then go to Step 7.

STEP 2. Check the ASC OFF switch.
Refer to 

P.35C-139

.

Q: Is the check result normal?

YES : 

Go to Step 3.

NO : 

Replace the ASC OFF switch (Refer to 

P.35C-139

.). Then go to Step 7.

TROUBLESHOOTING

ACTIVE STABILITY & TRACTION CONTROL SYSTEM (ASTC)

35C-130

STEP 3. Check for open circuit in the wiring 
harness between A-48 ASTC-ECU connector and 
C-140 ASC OFF switch connector.
Check for open circuit in the wiring harness between 
A-48 ASTC-ECU connector terminal No.29 and C-
140 ASC OFF switch connector terminal No.1.

Q: Is the check result normal?

YES : 

Go to Step 4.

NO : 

Repair the wiring harness between the A-48 
ASTC-ECU terminal No.29 and the C-140 
ASC OFF switch connector terminal No.1. 
Then go to Step 7.

STEP 4. Voltage measurement at A-48 ASTC-ECU 
connector.
(1) Disconnect the A-48 ASTC-ECU connector.
(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between the A-48 ASTC-

ECU connector terminal No.29.

OK:

• When the ASC OFF switch is not 

pressed: System voltage

• When the ASC OFF switch is pressed: 

1 V or less 

Q: Is the check result normal?

YES : 

Go to Step 5.

NO : 

Go to Step 6.

STEP 5. Check for open circuit in the wiring 
harness between C-140 ASC OFF switch 
connector and the body earth.
Check for open circuit in the wiring harness between 
C-140 ASC OFF switch connector terminal No.2 and 
the body earth.

Q: Is the check result normal?

YES : 

Go to Step 6.

NO : 

Repair the wiring harness between the C-
140 ASC OFF switch connector terminal 
No.2 and the body earth. Then go to Step 7.

STEP 6. Retest the system

Q: Does ASC system cancelled, when the ASC OFF 

switch is push on?
YES : 

It can be assumed that this malfunction is 

intermittent. (Refer to GROUP 00, How to 
Use Troubleshooting/Inspection Service 
Points 

− How to Cope with Intermittent 

Malfunction ).

NO : 

Replace the hydraulic unit (integrated with 
ASTC-ECU) (Refer to 

P.35C-140

.). Then go 

to Step 7.

STEP 7. Retest the system

Q: Does ASC system cancelled, when the ASC OFF 

switch is push on?
YES : 

The procedure is complete.

NO : 

Return to Step 1.

Inspection Procedure 8: ASTC System dose not operate.

COMMENT
The fail-safe function is probably cancelling ASTC 
system. In this case, M.U.T.-III can be used to Retest 
each system by checking the diagnosis codes.

PROBABLE CAUSES

• Malfunction of the CAN bus line.

• Malfunction of the ASTC-ECU.

• Battery voltage low.

DIAGNOSIS

STEP 1. Hydraulic unit check
 Refer to 

P.35C-135

.

Q: Is the check result normal?

YES : 

Go to Step 2.

NO : 

Connect the brake pipes correctly, repair the 
external brake lines, or replace the hydraulic 
unit.

STEP 2. Verify that the condition described by 
the customer exists.

Q: Can any faults be found with the brake operation?

YES : 

Check the brake system related 

components except the ASTC system.

NO : 

The procedure is complete.

TROUBLESHOOTING

ACTIVE STABILITY & TRACTION CONTROL SYSTEM (ASTC)

35C-131

Inspection procedure 9: The initial check sound of hydraulic unit is loud.

CAUTION

When installing brake tube, match the axial 

centre of flare nut and brake tube with the centre 
of hole at the hydraulic unit side, and check that 
the fluid does not leak.
COMMENT ON TROUBLE SYMPTOM
The operation sound may be decreased by reducing 
the load at the rubber mount portion of the brake 
tube and hydraulic unit. 

PROBABLE CAUSES

• Improper installation of the hydraulic unit

• Improper installation of the brake tube

DIAGNOSIS PROCEDURE

DRIVING CHECK
(1) Turn the ignition switch from the "LOCK" (OFF) 

position to the "ON" position.

(2) When vehicle speed reaches 10 km/h, check the 

operating sound volume and compare it with that 
of the same model.

OK: The operating sound is the same vol-
ume or less by comparing with that of the 
same model.

Q: Is the check result normal?

YES : 

This diagnosis is complete.

NO : 

Carry out adjustment for hydraulic unit 
installation. (Refer to 

P.35C-135

).

DATA LIST REFERENCE TABLE

M1355001500700

The following items can be read by the M.U.T.-III 
from the ASTC-ECU input data.
When the system is normal.

Item No.

Check item

Check condition

Normal condition

01

FL wheel speed sensor

Perform a test run of the vehicle Speedometer display and 

M.U.T.-III display almost agree 
with each other.

02

FR wheel speed sensor

03

RL wheel speed sensor

04

RR wheel speed sensor

05

Power supply voltage

Always

System voltage

08

Lateral G sensor

Vehicle is stopped (on a level 
surface)

0 m/s

2

Vehicle is running

-14.7 

− 14.7 m/s

2

09

G-sensor

Vehicle is stopped (on a level 
surface)

0 m/s

2

Vehicle is running

-14.7 

− 14.7 m/s

2

10

Master cylinder pressure

-10 

− 30 MPa

11

Steering angle

-900 

− 900 deg

12

Yaw rate sensor

-130 

− 130 deg/s

13

Stop lamp switch

The brake pedal is depressed

ON

The brake pedal is released

OFF

28

TCL off switch

TCL off switch: ON

ON

TCL off switch: OFF

OFF

40

Under Cranking

Engine cranking

YES

Not engine cranking

NO

57

Lateral G sensor without Cal.

-20 to 20 m/s

2