Mitsubishi Lancer (4A9 engine). Manual - part 74
TROUBLESHOOTING
ACTIVE STABILITY CONTROL SYSTEM (ASC)
35C-149
Inspection Procedure 5: Brake warning lamp does not illuminate when the ignition switch is turned to
ON position (engine stopped).
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 ).
• Whenever ECU is replaced, ensure that the
CAN bus lines are normal.
• When the hydraulic unit (integrated with ASC-
ECU) is replaced, always carry out the calibra-
tion of the steering wheel sensor, the G and
yaw rate sensor and brake fluid pressure sen-
sor (Refer to
and
OPERATION
• ASC-ECU sends the illumination request signal
of the break warning lamp to the combination
meter through ETACS-ECU via the CAN commu-
nication.
• ASC-ECU illuminates brake warning lamp via
ETACS-ECU for approximately 3 seconds for
bulb check with the ignition switch turned to the
ON position.
COMMENTS ON TROUBLE SYMPTOM
This may be caused by faults in the CAN bus line,
ETACS-ECU, combination meter or ASC-ECU.
PROBABLE CAUSES
• Damaged wiring harness and connectors
• Malfunction of ETACS-ECU
• Malfunction of the combination meter
• ASC-ECU malfunction
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 7.
STEP 2. M.U.T.-III diagnosis code
Use M.U.T.-III to check the diagnosis code for the
ASC system.
Q: Is the diagnosis code set?
YES :
Carry out the diagnosis for the diagnosis
code (Refer to
).
NO :
Go to Step 3.
STEP 3. Actuator test of combination meter
Perform the following actuator test by the combina-
tion meter system, and check if the brake warning
lamp illuminates (Refer to GROUP 54A
− Combina-
tion Meter/Actuator Test Table ).
• Item No.07: Indicator 1
Q: Is the check result normal?
YES :
Go to Step 4.
NO :
Diagnose the combination meter. (Refer to
GROUP 54A
− Combination Meter/Trouble
Symptom Chart .) Then go to Step 7.
STEP 4. M.U.T.-III other system diagnosis code
Using M.U.T.-III, check that diagnosis code
No.U0141 is set by the combination meter system.
Q: Is the diagnosis code set?
YES :
Diagnose the combination meter (Refer to
GROUP 54A
− Combination Meter/
Diagnosis Code ). Then go to Step 7.
NO :
Go to Step 5.
STEP 5. M.U.T.-III other system diagnosis code
Using M.U.T.-III, check that diagnosis code
No.U0121 is set by the ETACS system.
Q: Is the diagnosis code set?
YES :
Perform troubleshooting on ETACS-ECU.
(Refer to GROUP 54A
− ETACS/Diagnosis
Code .) Then go to Step 7.
NO :
Go to Step 6.
STEP 6. Retest the system.
Q: Does the brake warning lamp turn ON and OFF
YES :
Intermittent malfunction (Refer to GROUP
00
− How to Use Troubleshooting/How to
Cope with Intermittent Malfunctions ).
NO :
Replace the hydraulic unit (integrated with
ASC-ECU) (Refer to
), and then
go to Step 7.
STEP 7. Retest the system.
Q: Does the brake warning lamp turn ON and OFF
normally?