Mitsubishi L200. Manual - part 464

TROUBLESHOOTING

ACTIVE STABILITY & TRACTION CONTROL SYSTEM (ASTC)

35C-112

Q: Is code No.U1204 set?

YES : 

Replace the hydraulic unit (integrated with 

ASTC-ECU) (Refer to 

P.35C-140

). Then go 

to Step 4.

NO : 

The procedure is complete.

STEP 4. Check whether the diagnosis code is 
reset.
(1) Turn the ignition switch to the "ON" position.
(2) Erase the diagnosis code.

(3) Turn the ignition switch to the "LOCK" (OFF) 

position.

(4) Turn the ignition switch to the "ON" position.
(5) Check if the diagnosis code is set.
(6) Turn the ignition switch to the "LOCK" (OFF) 

position.

Q: Is code No.U1204 set?

YES : 

Go to Step 1.

NO : 

The procedure is complete.

Code No.U1205: G and yaw rate sensor message counter error

CAUTION

• If diagnosis code No.U1205 is set in the 

ASTC-ECU, always diagnose the CAN main 
bus line. If there is any fault in the CAN bus 
lines, an incorrect diagnosis code may be set.

• Whenever the ECU is replaced, ensure that 

the communication circuit is normal.

OPERATION
ASTC-ECU receives the longitudinal and lateral G 
detected by the G and yaw rate sensor via the CAN 
bus line.

DIAGNOSIS CODE SET CONDITION
This diagnosis code is set when the ASTC-ECU 
power supply voltage is normal but the signal sent 
from the G and yaw rate sensor differs from the sig-
nal sent at the previous time by more than the speci-
fied value.

PROBABLE CAUSES

• Noise generated in the CAN bus line

• Damaged harness or connector.

• Malfunction of the G and yaw rate sensor.

• Malfunction of the ASTC-ECU.

DIAGNOSIS PROCEDURE

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

Q: Is the check result normal?

YES : 

Go to Step 2.

NO : 

Repair the CAN bus lines (Refer to GROUP 
54C 

− CAN Bus Diagnostics Table ). Then 

go to Step 4.

STEP 2. M.U.T.-III diagnosis code
(1) Turn the ignition switch to the "ON" position.
(2) Erase the diagnosis code.

(3) Turn the ignition switch to the "LOCK" (OFF) 

position.

(4) Turn the ignition switch to the "ON" position.
(5) Check if the diagnosis code is set.
(6) Turn the ignition switch to the "LOCK" (OFF) 

position.

Q: Is code No.U1205 set?

YES : 

Replace the G and yaw rate sensor (Refer 

to 

P.35C-142

). Then go to Step 3.

NO : 

Intermittent malfunction (Refer to GROUP 
00 

− How to Cope with Intermittent 

Malfunction ).

STEP 3. M.U.T.-III diagnosis code
(1) Turn the ignition switch to the "ON" position.
(2) Erase the diagnosis code.
(3) Turn the ignition switch to the "LOCK" (OFF) 

position.

(4) Turn the ignition switch to the "ON" position.
(5) Check if the diagnosis code is set.
(6) Turn the ignition switch to the "LOCK" (OFF) 

position.

Q: Is code No.U1205 set?

YES : 

Replace the hydraulic unit (integrated with 

ASTC-ECU) (Refer to 

P.35C-140

). Then go 

to Step 4.

NO : 

The procedure is complete.

STEP 4. Check whether the diagnosis code is 
reset.
(1) Turn the ignition switch to the "ON" position.
(2) Erase the diagnosis code.
(3) Turn the ignition switch to the "LOCK" (OFF) 

position.

(4) Turn the ignition switch to the "ON" position.
(5) Check if the diagnosis code is set.
(6) Turn the ignition switch to the "LOCK" (OFF) 

position.

TROUBLESHOOTING

ACTIVE STABILITY & TRACTION CONTROL SYSTEM (ASTC)

35C-113

Q: Is code No.U1205 set?

YES : 

Go to Step 1.

NO : 

The procedure is complete.

TROUBLE SYMPTOM CHART

M1355006900435

CAUTION

• ABS may operate in the following conditions without hard braking: Low mu road surface, high-

speed turn, and bumpy road surface. When asking the customers, confirm that they have/have not 
encountered ABS operation in corresponding conditions.

• During ABS operation, the brake pedal is pulled forward gradually, and the noise occurs at the 

same time. This is because the brake line pressure varies intermittently to prevent the wheel lock, 
and not a system malfunction.

• 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, confirm all systems for diag-
nosis code(s). If diagnosis code(s) are set, erase them all.

Trouble symptom

Inspection 
procedure 
number

Reference 
page

M.U.T.-III cannot communicate with 
the ASTC system.

M.U.T.-III cannot communicate with 
all systems.

−

Refer to 
GROUP 54C 
− 
Troubleshooti
ng .

M.U.T.-III cannot communicate only 
with ASTC-ECU.

1

P.35C-113

ASTC OFF indicator lamp flashes at a rate of 2Hz.

2

P.35C-114

Brake warning lamp stays ON with the parking brake lever or the parking 
brake stick released (ABS warning lamp is OFF).

3

P.35C-115

ABS warning lamp remains illuminated after the engine is started.

4

P.35C-119

ASTC indicator lamp stays ON after the engine is started.

5

P.35C-122

ASTC OFF indicator lamp stays ON after the engine is started.

6

P.35C-125

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

7

P.35C-128

ASTC system dose not operate.

8

P.35C-130

The initial check sound of hydraulic unit is loud.

9

P.35C-131

SYMPTOM PROCEDURES

Inspection Procedure 1: M.U.T.-III cannot communicate only with ASTC-ECU.

CAUTION

• If there is any problem in the CAN bus lines, 

an incorrect diagnosis code may be set. Prior 
to this diagnosis, diagnose the CAN bus lines 
(Refer to GROUP 54C 

− CAN Bus Diagnostics 

Table ).

• Before replacing the ECU, ensure that the 

communication circuit is normal.

TECHNICAL DESCRIPTION (COMMENT)
If the M.U.T.-III cannot communicate with the ASTC 
system, the CAN bus lines may be defective. If the 
ASTC system does not work, the ASTC-ECU or its 
power supply circuit may be defective. 

PROBABLE CAUSES

• Damaged wiring harness and connectors

• ASTC-ECU malfunction

TROUBLESHOOTING

ACTIVE STABILITY & TRACTION CONTROL SYSTEM (ASTC)

35C-114

• Wrong routing of M.U.T.-III harness

• Abnormality in battery or alternator

• Abnormality in power supply voltage to ASTC-

ECU

• ECU malfunction of other system

DIAGNOSIS

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

Q: Is the check result normal?

YES : 

Check the power supply circuit system 

(Refer to 

P.35C-100

).

NO : 

Repair the CAN bus lines (Refer to GROUP 
54C 

− CAN Bus Diagnostics Table ).

Inspection Procedure 2: ASTC OFF indicator lamp flashes at a rate of 2Hz

OPERATION
When the ASTC OFF indicator lamp flashes at a rate 
of 2 Hz, the ASTC is prohibited.

COMMENTS ON TROUBLE SYMPTOM
This operation is performed for the following reasons 
and is not a malfunction.

• ASTC-ECU calculates the estimated temperature 

of the brake pad. In general, as the brake pad 
temperature increases, the coefficient of friction 
for the brake pad becomes smaller, resulting in 
the reduced braking force. When the estimated 

temperature of the brake pad reaches the speci-
fied value or more, ASTC-ECU flashes the ASTC 
OFF indicator lamp at a rate of 2 Hz to warn the 
driver that the brake controllability by ASTC is 
decreased by the reduced braking force. Conse-
quently, ASTC-ECU prohibits the ASTC control 
until it determines that the estimated temperature 
of the brake pad is normal.

PROBABLE CAUSES

• Overheat of brake pad

TROUBLESHOOTING

ACTIVE STABILITY & TRACTION CONTROL SYSTEM (ASTC)

35C-115

Inspection Procedure 3: Brake warning lamp stays ON with the parking brake lever or the parking 
brake stick released (ABS warning lamp is OFF).

Combination Meter Circuit

ASTC-ECU

IGNITION 
SWITCH (IG1)

COMBINATION 
METER

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

ACB00856

19

14

13

1

3

15

2

16

4

18

6

17

5

7

22

10

21

20

8 9

23

11

24

12

PARKING 
BRAKE 
SWITCH

PARKING 
BRAKE 
SWITCH

BRAKE 
FLUID 
LEVEL 
SWITCH

<LEVER TYPE>

<STICK TYPE>

NOTE

LHD

NOTE

: 

RHD

: