Mitsubishi Evolution X. Manual - part 785

DIAGNOSIS

TSB Revision

ACTIVE SKID CONTROL SYSTEM (ASC)

35C-147

PROBABLE CAUSES

• Steering wheel sensor malfunction

• G and yaw rate sensor malfunction

• Improper installation of steering wheel sensor or G and yaw 

rate sensor

• ASC-ECU malfunction

• Different steering wheel

• Wheel alignment not performed

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 C123B set?

YES : Go to Step 3.
NO :  This diagnosis is complete.

STEP 3. Scan tool diagnostic trouble code
Check that DTCs C100A, C1015, C1020, C102B, C1011, 
C101C, C1027, C1032, C1014, C101F, C102A, C1035, C1041, 
C1042, C1043, C1044, C1219, C2205, C123C, and C2204 are 
also set.
Q: Are DTCs C100A, C1015, C1020, C102B, C1011, C101C, 

C1027, C1032, C1014, C101F, C102A, C1035, C1041, 
C1042, C1043, C1044, C1219, C2205, C123C, and C2204 
also set?
YES : Carry out the diagnosis for the diagnostic trouble 

code that is set. (Refer to 

P.35C-20

.) Then go to Step 

10.

NO :  Go to Step 4.

DIAGNOSIS

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ACTIVE SKID CONTROL SYSTEM (ASC)

35C-148

STEP 4. Check of G and yaw rate sensor installation status
Check that the G and yaw rate sensor is installed correctly.
Q: Is the check result normal?

YES : After checking the G and yaw rate sensor, perform 

the calibration of the G and yaw rate sensor to make 
ASC-ECU relearn the neutral point.(Refer to 

P.35C-266

.) Then go to Step 5.

NO :  Reinstall the G and yaw rate sensor correctly. (Refer 

to 

P.35C-278

.) Then go to Step 10.

STEP 5. Scan tool service data
Check the following service data. (Refer to 

P.35C-255

.)

• Item 08: Lateral G sensor

• Item 09: G sensor

• Item 12: Yaw rate sensor

Q: Is the check result normal?

YES : Go to Step 6.
NO :  Replace the G and yaw rate sensor. (Refer to 

P.35C-278

.) Then go to Step 10.

STEP 6. Check of steering wheel sensor installation status
Check that the steering wheel sensor is installed correctly.
Q: Is the check result normal?

YES : Go to Step 7.
NO :  Install the steering wheel sensor correctly. (Refer to 

P.35C-279

.) Then go to Step 7.

STEP 7. Wheel alignment check
Refer to 

P.33-7

.

Q: Is the check result normal?

YES : After checking the wheel alignment, perform the 

calibration of steering wheel sensor to make 
ASC-ECU relearn the neutral point.(Refer to 

P.35C-267

.) Then go to Step 8.

NO :  After adjusting the wheel alignment, perform the 

calibration of steering wheel sensor to make 
ASC-ECU relearn the neutral point.(Refer to 

P.35C-267

.) Then go to Step 8.

STEP 8. Scan tool service data
Check the following service data. (Refer to 

P.35C-255

.)

• Item 11: Steering angle

Q: Is the check result normal?

YES : Go to Step 9.
NO :  Replace the steering wheel sensor. (Refer to 

P.35C-279

.) Then go to Step 10.

DIAGNOSIS

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ACTIVE SKID CONTROL SYSTEM (ASC)

35C-149

STEP 9. Check whether the DTC is reset.
Q: Is DTC C123B set?

YES : Replace the hydraulic unit (incorporates in 

ASC-ECU).(Refer to 

P.35C-272

.) Then go to Step 10.

NO :  Intermittent malfunction. (Refer to GROUP 00 

− How 

to Cope with Intermittent Malfunction 

P.00-15

.)

STEP 10. Check whether the DTC is reset.
Q: Is DTC C123B set?

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

DTC C2200: Abnormality in ASC-ECU

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 hydraulic unit (integrated with ASC-ECU) is 

replaced, always perform the calibration of steering 
wheel sensor, G and yaw rate sensor, brake fluid pres-
sure sensor, cut valve, and inlet valve.(Refer to 

P.35C-266

, 

P.35C-267

, 

P.35C-268

, and 

P.35C-269

.)

.

CIRCUIT OPERATION

ASC-ECU controls ASC by calculating the data sent from the 
wheel speed sensor, steering wheel sensor, and G and yaw 
rate sensor.

.

DTC SET CONDITIONS

This diagnostic trouble code is set when ASC-ECU has mal-
function.

.

PROBABLE CAUSES

ASC-ECU malfunction

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

DIAGNOSIS

TSB Revision

ACTIVE SKID CONTROL SYSTEM (ASC)

35C-150

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 2.
NO :  Repair the CAN bus lines. (Refer to GROUP 54C 

− 

Troubleshooting 

P.54C-14

.) After repairing the CAN 

bus line, go to Step 3.

STEP 2. Check whether the DTC is reset.
Q: Is DTC C2200 set?

YES : Replace the hydraulic unit (incorporates in 

ASC-ECU).(Refer to 

P.35C-272

.) Then go to Step 3.

NO :  Intermittent malfunction. (Refer to GROUP 00 

− How 

to Cope with Intermittent Malfunction 

P.00-15

.)

STEP 3. Check whether the DTC is reset.
Q: Is DTC C2200 set?

YES : Return to Step 1.
NO :  This diagnosis is complete.

DTC C2101: Abnormality in battery voltage (high voltage)

AC708948

Connector: A-05

A-05 (B)

AB

AC708950

Connectors: C-103, 130

AJ

C-103 (B)

C-130 (BR)

AC708972AM

Connectors: C-309, C-315

C-309 (B)

C-315

ETACS-ECU