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.