Mitsubishi L200. Manual — part 452

TROUBLESHOOTING

ACTIVE STABILITY & TRACTION CONTROL SYSTEM (ASTC)

35C-64

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

position.

Q: Is code No.C1226, C1231, C1236, C1241, C1246,

C1251, C1256, C1261, C1300 or C1310 set?
YES :

Go to Step 1.

NO :

The procedure is complete.

Code No.C1266: Motor system

Code No.C1273: Motor relay (stuck off)

Code No.C1274: Motor relay (stuck on)

Code No.C1280: Motor fail-safe relay (short circuit)

Solenoid Valve and Motor Power Supply Circuit

MOTOR
POWER
SOURCE

MOTOR
POWER
SOURCE

SOLENOID
VALVE
POWER
SOURCE

FUSIBLE
LINK

22

FUSIBLE
LINK

21

MOTOR SOLENOID

VALVE

HYDRAULIC UNIT

ASTC-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

ACB00773

AC800980

AG

Connector: A-48

(B)

TROUBLESHOOTING

ACTIVE STABILITY & TRACTION CONTROL SYSTEM (ASTC)

35C-65

CAUTION

If there is any problem in the CAN bus lines, an
incorrect diagnosis code may be set. Diagnose
the CAN bus lines before the diagnosis codes
(Refer to GROUP 54C

− CAN Bus Diagnostics

Table .).
OPERATION

• The ASTC-ECU contains the power supply circuit

(terminal 13) for the motor. ACTS-ECU incorpo-
rates a monitor to check if power is supplied to
the motor for running.

• The pump motor switch, which is incorporated in

ASTC-ECU, is always off unless the ABS operat-
ing or the motor solenoid valve check is activated
when the vehicle is started.

• ASTC-ECU activates the pump motor by turning

on the ECU built-in pump motor switch.

DIAGNOSIS CODE SET CONDITIONS
These diagnosis code will be set under the cases
below.

Code No. C1266

• An open circuit has occurred to motor relay moni-

tor.

• Motor is seized.

Code No. C1273

• At an initial start, the motor relay monitor judges

the status of the motor relay as "OFF," and the
motor is driven.

Codes No. C1274 or C1280

• When the motor relay monitor judges that the

motor relay is "ON" while it is "OFF".

PROBABLE CAUSES
The most likely causes for these diagnosis codes to
set are:

• Fusible link malfunction

• Damaged wiring harness or connector

• Malfunction of the hydraulic unit assembly (inte-

grated with ASTC-ECU)

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnosis.
Use 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
54C

− CAN Bus Diagnostics Table .). On

completion, go to Step 2.

STEP 2. Diagnosis code recheck after resetting
CAN bus lines.
(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) Drive the vehicle at 10 km/h or more.
(6) Check if the diagnosis code is set.
(7) Turn the ignition switch to the "LOCK" (OFF)

position.

Q: Are diagnosis codes No.C1266, C1273, C1274 or

C1280 set?
YES :

Go to Step 3.

NO :

The procedure is complete.

STEP 3. Connector check: A-48 ASTC-ECU
connector

Q: Is the check result normal?

YES :

Go to Step 4.

NO :

Repair or replace the damaged
component(s). Then go to Step 9.

STEP 4. Fusible link check: Check the fusible link
No.22

Q: Is the check result normal?

YES :

Go to Step 6.

NO :

Go to Step 5.

STEP 5. Resistance measurement at A-48 ASTC-
ECU connector
(1) Removal the fusible link No.22.
(2) Disconnect the A-48 ASTC-ECU connector.
(3) Measure the resistance between the A-48 ASTC-

ECU connector terminal No.13 and body earth.

OK: No continuity

Q: Is the check result normal?

TROUBLESHOOTING

ACTIVE STABILITY & TRACTION CONTROL SYSTEM (ASTC)

35C-66

YES :

Replace the fusible link No.22. Then go to

Step 9.

NO :

Repair the wiring harness between the
fusible link No.22 and A-48 ASTC-ECU
connector terminal No.13. Then replace the
fusible link No.22. Then go to Step 9.

STEP 6. Voltage measurement at the A-48 ASTC-
ECU connector
(1) Disconnect the A-48 ASTC-ECU connector.
(2) Measure the voltage between the A-48 ASTC-

ECU connector terminal No.13 and the body
earth.

OK: Battery voltage

Q: Is the check result normal?

YES :

Go to Step 7.

NO :

The open circuit may be present in the
motor power supply circuit. Repair the
wiring harness between the A-48 ASTC-
ECU connector terminal No.13 and the
fusible link No.22. Then go to Step 9.

STEP 7. Resistance measurement at A-48 ASTC-
ECU connector
(1) Disconnect the A-48 ASTC-ECU connector.
(2) Measure the resistance between the A-48 ASTC-

ECU connector terminal No.12 and the body
earth, and between the terminal No.24 and body
earth.

OK: Continuity exists (2

Ω or less)

Q: Is the check result normal?

YES :

Go to Step 8.

NO :

The open circuit may be present in the earth
circuit. Repair the wiring harness between
the A-48 ASTC-ECU connector terminal
No.12 and the body earth, and between the
A-48 ASTC-ECU connector terminal No.24
and the body earth. Then go to Step 9.

STEP 8. Check whether the diagnosis code is
reset.
Check again if the diagnosis code is set.
(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) Drive the vehicle at 10 km/h or more.
(6) Check if the diagnosis code is set.
(7) Turn the ignition switch to the "LOCK" (OFF)

position.

Q: Are diagnosis codes No.C1266, C1273, C1274 or

C1280 set?
YES :

Replace the hydraulic unit assembly

(integrated with ASTC-ECU) (Refer to

P.35C-140

.). Then go to Step 9.

NO :

Intermittent malfunction (Refer to GROUP
00

− How to Cope with Intermittent

Malfunctions .).

STEP 9. Check whether the diagnosis code is
reset.
Check again if the diagnosis code is set.
(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) Drive the vehicle at 10 km/h or more.
(6) Check if the diagnosis code is set.
(7) Turn the ignition switch to the "LOCK" (OFF)

position.

Q: Are diagnosis codes No.C1266, C1273, C1274 or

C1280 set?
YES :

Go to Step 1.

NO :

This diagnosis is complete.

TROUBLESHOOTING

ACTIVE STABILITY & TRACTION CONTROL SYSTEM (ASTC)

35C-67

Code No.C1278: Solenoid valve relay (open circuit)

Code No.C1279: Solenoid valve relay (short circuit)

Solenoid Valve and Motor Power Supply Circuit

MOTOR
POWER
SOURCE

MOTOR
POWER
SOURCE

SOLENOID
VALVE
POWER
SOURCE

FUSIBLE
LINK

22

FUSIBLE
LINK

21

MOTOR SOLENOID

VALVE

HYDRAULIC UNIT

ASTC-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

ACB00773

AC800980

AG

Connector: A-48

(B)

CAUTION

If there is any problem in the CAN bus lines, an
incorrect diagnosis code may be set. Diagnose
the CAN bus lines before the diagnosis codes
(Refer to GROUP 54C

− CAN Bus Diagnostics

Table .).
OPERATION
ASTC-ECU receives the power supply to drive the
incorporated solenoid valves at terminal No.1. Each
solenoid valve has a relay for driving. ASTC-ECU
turns the relay of the solenoid valve to be driven ON
or OFF to switch the hydraulic circuit.