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Mitsubishi Evolution X. Manual - part 794

DIAGNOSIS

TSB Revision

ACTIVE SKID CONTROL SYSTEM (ASC)

35C-183

DIAGNOSIS

Required Special Tools:

• MB991958 Scan Tool (M.U.T.-III Sub Assembly)

• MB991824: Vehicle Communication Interface (V.C.I.)

• MB991827 M.U.T.-III USB Cable

• MB991910 M.U.T.-III Main Harness A

STEP 1. Using scan tool MB991958, diagnose the CAN bus
lines.
Using scan tool MB991958, 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

−

Troubleshooting

P.54C-14

.) After repairing the CAN

bus line, go to Step 2.

STEP 2. DTC recheck after repairing the CAN bus line
Q: Is DTC C123A set?

YES : Go to Step 3.
NO : The procedure is complete.

STEP 3. Check for diagnostic trouble codes of other
systems
Check if the diagnostic trouble code is set related to the G and
yaw rate sensor, steering wheel sensor, and master cylinder
pressure sensor.
Q: Is any DTC set?

YES : Go to Step 4.
NO : Carry out the diagnosis for the diagnostic trouble code

that is set. (Refer to

P.35C-20

STEP 4. G and yaw rate sensor calibration
Perform calibration of the G and yaw rate sensor. ( Refer to

P.35C-266

Q: Has the calibration succeeded?

YES : Go to Step 5.
NO : Replace the hydraulic unit (incorporates in

ASC-ECU).(Refer to

P.35C-272

.) Then go to Step 8.

STEP 5. Steering wheel sensor calibration
Perform calibration of the steering wheel sensor. ( Refer to

P.35C-267

Q: Has the calibration succeeded?

YES : Go to Step 6.
NO : Replace the hydraulic unit (incorporates in

ASC-ECU).(Refer to

P.35C-272

.) Then go to Step 8.

DIAGNOSIS

TSB Revision

ACTIVE SKID CONTROL SYSTEM (ASC)

35C-184

STEP 6. Master cylinder pressure sensor calibration
Perform calibration of the brake fluid pressure sensor. ( Refer
to

P.35C-268

Q: Has the calibration succeeded?

YES : Go to Step 7.
NO : Replace the hydraulic unit (incorporates in

ASC-ECU).(Refer to

P.35C-272

.) Then go to Step 8.

STEP 7. Check whether the DTC is reset.
Q: Is DTC C123A set?

YES : Replace the hydraulic unit (incorporates in

ASC-ECU).(Refer to

P.35C-272

.) Then go to Step 8.

NO : Intermittent malfunction. (Refer to GROUP 00

− How

to Cope with Intermittent Malfunction

P.00-15

STEP 8. Check whether the DTC is reset.
Q: Is DTC C123A set?

YES : Return to Step 1.
NO : The procedure is complete.

DTC C1219: Abnormality in steering wheel sensor signal

CAUTION

• If there is any problem in the CAN bus lines, an incor-

rect diagnostic trouble code may be set. Prior to this
diagnosis, diagnose the CAN bus lines.

• Whenever the ECU is replaced, ensure that the CAN

bus lines are normal.

• When the steering wheel sensor is replaced, always

perform calibration to make ASC-ECU learn the neutral
point. (Refer to

P.35C-267

• Do not drop the G and yaw rate sensor or subject it to a

shock.

• When the G and yaw rate sensor is replaced, always

perform the calibration to make ASC-ECU learn the
neutral point. (Refer to

P.35C-266

• When the hydraulic unit (integrated with ASC-ECU) is

replaced, after turning the ignition switch ON and OFF
(vehicle information from ETACS-ECU is registered),
always perform the calibration of steering wheel sen-
sor, G and yaw rate sensor, brake fluid pressure sen-
sor, cut valve, and inlet valve.(Refer to

, and

CIRCUIT OPERATION

Steering wheel sensor outputs the signal to ASC-ECU via CAN
bus lines.

DIAGNOSIS

TSB Revision

ACTIVE SKID CONTROL SYSTEM (ASC)

35C-185

DTC SET CONDITIONS

This diagnostic trouble code is set if any malfunction below is
found:

• The tolerance of the neutral position of steering wheel sen-

sor exceeds the specified range.

• Abnormality in steering wheel sensor output value

• Abnormality is detected by a comparison of output value

from the steering wheel sensor with the output values from
wheel speed sensor and G and yaw rate sensor.

PROBABLE CAUSES

• Improper installation of steering wheel sensor

• Wheel alignment not performed

• Steering wheel sensor malfunction

• Different steering wheel

• G and yaw rate sensor malfunction

• Wheel speed sensor malfunction

• ASC-ECU malfunction

• External noise interference

DIAGNOSIS

Required Special Tools:

• MB991958 Scan Tool (M.U.T.-III Sub Assembly)

• MB991824: Vehicle Communication Interface (V.C.I.)

• MB991827 M.U.T.-III USB Cable

• MB991910 M.U.T.-III Main Harness A

STEP 1. Using scan tool MB991958, diagnose the CAN bus
lines.
Using scan tool MB991958, 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

−

Troubleshooting

P.54C-14

.) After repairing the CAN

bus line, go to Step 2.

STEP 2. DTC recheck after repairing the CAN bus line
Q: Is DTC C1219 set?

YES : Go to Step 3.
NO : The procedure is complete.

STEP 3. Check the DTC.
Check if the wheel speed sensor-related, G and yaw rate sen-
sor-related, or steering wheel sensor-related diagnostic trouble
code is set.
Q: Is any DTC set?

YES : Troubleshoot the relevant diagnostic trouble code,

and then go to Step 8.

NO : Go to Step 4.

DIAGNOSIS

TSB Revision

ACTIVE SKID CONTROL SYSTEM (ASC)

35C-186

STEP 4. Check of steering wheel sensor installation status
Check that the steering wheel sensor is installed correctly.
(Refer to

P.35C-279

Q: Is the check result normal?

YES : Go to Step 5.
NO : Install the steering wheel sensor correctly. (Refer to

P.35C-279