Mitsubishi Lancer (4A9 engine). Manual - part 46
AC612691
AO
Connector: A-58 <LHD>
A-58 (B)
TROUBLESHOOTING
ACTIVE STABILITY CONTROL SYSTEM (ASC)
35C-37
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
• The wheel speed sensor is a kind of a pulse gen-
erator. It consists of encoders (a plate on which
north and south pole sides of the magnets are
arranged alternately) for detecting the wheel
speed which rotates at the same speed of the
wheels and wheel speed sensors. This sensor
outputs frequency pulse signals in proportion to
the wheel speed.
• The pulse signals, which the wheel speed sensor
creates, are sent to ASC-ECU. ASC-ECU uses
the frequency of the pulse signals to determine
the wheel speed.
DIAGNOSIS CODE SET CONDITIONS
ASC-ECU monitors the signals from each wheel
speed sensor while the vehicle is being driven. If any
fault below is found in these sensor signals, ASC-
ECU will set the relevant diagnosis code.
• Irregular change in the wheel speed sensor sig-
nal
• Wheel speed sensor signal continuously indi-
cates high value.
PROBABLE CAUSES
Current trouble
• Excessive gap between the wheel speed sensor
and the wheel speed detection encoder
• Adhesion of foreign materials on the wheel speed
sensor
• Adhesion of foreign materials on the wheel speed
detection encoder
• Wheel bearing malfunction
• Malfunction of wheel speed sensor
• Damaged wiring harness and connectors
• External noise interference
• Improper installation of the wheel speed sensor
• Deformation of the wheel speed detection
encoder
• ASC-ECU malfunction
• Disturbance of magnetisation pattern for wheel
speed detection encoder
• The number of poles on the Magnetic encoder for
wheel speed detection (N-pole and S-pole) is
changed
Past trouble
• When diagnosis code No.C100A is also set, carry
out diagnosis with particular emphasis on wiring
harness and connector failures between ASC-
ECU and the wheel speed sensor. For diagnosis
procedures, refer to How to treat past trouble
(GROUP 00
− How to Use Troubleshooting/How
to Treat Past Trouble ).
• When diagnosis code No.C100A is not set, the
following conditions may be present:
• Some wheels slip
• Unstable vehicle attitude
• External noise interference
• Vehicle ran with the parking brake applied
DIAGNOSTIC 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
Q: Is the diagnosis code No.C1011 set?
YES :
Go to Step 3.
NO :
This diagnosis is complete.
STEP 3. M.U.T.-III diagnosis code
Check that diagnosis code No.C100A is also set.
Q: Is diagnosis code No.C100A also set?