Mitsubishi L200. Manual — part 428

TROUBLESHOOTING

ANTI-SKID BRAKING SYSTEM (ABS)

35B-33

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.

OPERATION

• ABS-ECU contains the power supply circuit (ter-

minal No.13) for the pump motor. The pump
motor is energised by the motor switch, which is
incorporated in ABS-ECU.

• The pump motor switch, which is incorporated in

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

• ABS-ECU activates the pump motor by turning

on the ECU built-in pump motor switch.

DIAGNOSIS CODE SET CONDITIONS
These diagnosis codes 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.

Code No. C1274

• When the motor relay monitor judges that the

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

PROBABLE CAUSES

Current trouble

• Fusible link malfunction

• Damaged wiring harness and connectors

• ABS-ECU malfunction

Past trouble

• Carry out diagnosis with particular emphasis on

wiring harness and connector failures between
the power supply circuit (A-01 ABS-ECU connec-
tor terminal No.13) to the ABS-ECU motor and
the earth circuit (A-01 ABS-ECU connector termi-
nal No.12 and No.24). For diagnosis procedures,
refer to How to treat past trouble (GROUP 00

−

How to Cope with Intermittent Malfunctions ).

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 Diagnosis Table .). On

completion, go to Step 2.

STEP 2. Diagnosis code recheck after resetting
CAN bus lines

• Erase the diagnosis code.

• Drive the vehicle at 10 km/h or more.

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

set?
YES :

Go to Step 3.

NO :

This diagnosis is complete.

STEP 3. Connector check: A-01 ABS-ECU
connector

Q: Is the check result normal?

YES :

Go to Step 4.

NO :

Repair the defective connector. 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-01 ABS-
ECU connector
(1) Removal the fusible link No.22.
(2) Disconnect the A-01 ABS-ECU connector.
(3) Measure the resistance between the terminal

No.13 and the body earth.

OK: No continuity

Q: Is the check result normal?

YES :

Replace the fusible link No.22. Then go to

Step 9.

NO :

Repair the harness between the fusible link
No.22 and A-01 ABS-ECU connector
terminal No.13. Then replace the fusible link
No.22. Then go to Step 9.

STEP 6. Voltage measurement at the A-01 ABS-
ECU connector
(1) Disconnect the A-01 ABS-ECU connector.

TROUBLESHOOTING

ANTI-SKID BRAKING SYSTEM (ABS)

35B-34

(2) Measure the voltage between the 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
pump motor power supply circuit. Repair the
wiring harness between the A-01 ABS-ECU
connector terminal No.13 and the fusible
link No.22. Then go to Step 9.

STEP 7. Resistance measurement at A-01 ABS-
ECU connector
(1) Disconnect the A-01 ABS-ECU connector.
(2) Measure the resistance between the terminal

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

OK: Continuity exists (2

Ω or less)

Q: Is the check result normal?

YES :

Go to Step 8.

NO :

An open circuit may be present in the earth
circuit. Repair the wiring harness between
the A-01 ABS-ECU terminal No.12 and the
body earth, and between the A-01 ABS-
ECU terminal No.24 and the body earth.
Then go to Step 9.

STEP 8. Check whether the diagnosis code is
reset.

• Erase the diagnosis code.

• Drive the vehicle at 10 km/h or more.

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

set?
YES :

Replace the hydraulic unit (integrated with

ABS-ECU) (Refer to

P.35B-60

). 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.

• Erase the diagnosis code.

• Drive the vehicle at 10 km/h or more.

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

set?
YES :

Return to Step 1.

NO :

This diagnosis is complete.

TROUBLESHOOTING

ANTI-SKID BRAKING SYSTEM (ABS)

35B-35

Code No. C1340: Stop lamp switch malfunction <short circuit (short to power supply)>

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 SI : Silver

FUSIBLE
LINK

23

RELAY
BOX

STOP LAMP
SWITCH

HIGH-
MOUNTED
STOP
LAMP

REAR
COMBINATION
LAMP
(STOP: LH)

REAR
COMBINATION
LAMP
(STOP: RH)

NOTE

: WITH REAR BODY
: WITHOUT REAR BODY

ABS-ECU

AC809288

NOTE

:

ACB00769

: LHD
: RHD

AC501971

Connector: A-01

AU

(B)

AC600687CC

Connector: C-114 <LHD>

Harness side
connector

4

1

2

3

AC600623

Harness side
connector

CJ

Connector: C-114 <RHD>

4

1

2

3

AC600687CD

Connectors: C-10, C-30 <LHD>

C-10

C-30

C-10

C-30

6 7

1 2

11

8 9 10

3 4

12

5

AC600688

Connector: C-13 <LHD>

BS

AC600623CK

Connector: C-10, C-13 <RHD>

C-13

C-10

C-13

6 7

1 2

11

8 9 10

3 4

12

5

C-10

AC600635BH

Connector: C-30 <RHD>

AC809345 AB

Connectors: F-02, F-03, F-04, F-07, F-19, F-22

F-07 (B)

F-03 (B)

F-02 (B)

<Vehicles without
rear body>

F-04 (B)

F-19

F-22

2 1

3

1

2

6

5

4

F-03
Harness connector

F-07

F-19, F-22
Harness connector

2
5

6

3

4

1

F-02, F-04
Harness connector

TROUBLESHOOTING

ANTI-SKID BRAKING SYSTEM (ABS)

35B-36

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.

OPERATION
ABS-ECU monitors whether the stop lamp switch is
"ON" or "OFF."