Mitsubishi Evolution X. Manual - part 793

DIAGNOSIS

TSB Revision

ACTIVE SKID CONTROL SYSTEM (ASC)

35C-179

DTC SET CONDITIONS

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

DTC C2114

• When the power supply voltage applied from ASC-ECU to 

the G and yaw rate sensor is not within the standard value 
range (low)

DTC C2115

• When the power supply voltage applied from ASC-ECU to 

the G and yaw rate sensor is not within the standard value 
range (high)

.

PROBABLE CAUSES

• Damaged wiring harness and connectors

• G and yaw rate sensor malfunction

• 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

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 2.

STEP 2. Check for diagnostic trouble codes of other 
systems
Check if diagnostic trouble code No. U0125 is also set in 
ASC-ECU.
Q: Is DTC U0125 set?

YES : Perform troubleshooting for the diagnostic trouble 

code that is set. (Refer to 

P.35C-202

.) Then go to 

Step 3.

NO :  Go to Step 3.

STEP 3. DTC recheck after repairing the CAN bus line
Q: Is DTC C2114 or C2115 set?

YES : Go to Step 4.
NO :  The procedure is complete.

DIAGNOSIS

TSB Revision

ACTIVE SKID CONTROL SYSTEM (ASC)

35C-180

STEP 4. 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 12.
NO :  Go to Step 5.

STEP 5. G and yaw rate sensor installation check
Check that the G and yaw rate sensor is installed correctly.
Q: Is the check result normal?

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

to 

P.35C-278

.) Then go to Step 13.

STEP 6. Connector check: A-05 ASC-ECU connector, C-38 
G and yaw rate sensor connector
Q: Is the check result normal?

YES : Go to Step 7.
NO :  Repair the defective connector.

STEP 7. Voltage measurement at C-38 G and yaw rate 
sensor connector
(1) Disconnect the connector.
(2) Turn the ignition switch to the ON position.
(3) Measure the voltage between the terminal No.1 and the 

body ground.

OK: System voltage

Q: Is the check result normal?

YES : Go to Step 10.
NO :  Go to Step 8.

DIAGNOSIS

TSB Revision

ACTIVE SKID CONTROL SYSTEM (ASC)

35C-181

STEP 8. Voltage measurement at A-05 ASC-ECU connector
(1) Disconnect the ASC-ECU connector, connect the ASC 

check harness (Special tool: MB991997) to the 
ASC-ECU-side connector and the wiring harness-side 
connector, and then measure at the special tool connector 
side.

(2) Disconnect C-38 G and yaw rate sensor connector.
(3) Turn the ignition switch to the ON position.
(4) Measure the voltage between the terminal No.22 and the 

body ground.

OK: System voltage

Q: Is the check result normal?

YES : Repair the wiring harness between A-05 ASC-ECU 

connector terminal No. 22 and C-38 G and yaw rate 
sensor connector terminal No. 1.

NO :  Go to Step 9.

STEP 9. Wiring harness check between A-05 ASC-ECU 
connector terminal No.22 and C-38 G and yaw rate sensor 
connector terminal No.1.

• Short circuit check of power supply circuit

Q: Is the check result normal?

YES : Go to Step 12.
NO :  Repair the wiring harness between A-05 ASC-ECU 

connector terminal No. 22 and C-38 G and yaw rate 
sensor connector terminal No. 1.

STEP 10. Wiring harness check between A-05 ASC-ECU 
connector terminal No.29 and C-38 G and yaw rate sensor 
connector terminal No.5.

• Open circuit check of the ground circuit

Q: Is the check result normal?

YES : Replace the G and yaw rate sensor. (Refer to 

P.35C-278

.) Then go to Step 11.

NO :  Repair the wiring harness between A-05 ASC-ECU 

connector terminal No. 29 and C-38 G and yaw rate 
sensor connector terminal No. 5.

STEP 11. Check whether the DTC is reset.
Q: Is DTC C2114 or C2115 set?

YES : Replace the hydraulic unit (incorporates in 

ASC-ECU).(Refer to 

P.35C-272

.) Then go to Step 13.

NO :  The procedure is complete.

AC400817CR

ASC-ECU

MB991997

Check harness

A-05 ASC-ECU
harness connector

DIAGNOSIS

TSB Revision

ACTIVE SKID CONTROL SYSTEM (ASC)

35C-182

STEP 12. Check whether the DTC is reset.
Q: Is DTC C2114 or C2115 set?

YES : Replace the hydraulic unit (incorporates in 

ASC-ECU).(Refer to 

P.35C-272

.) Then go to Step 13.

NO :  Intermittent malfunction. (Refer to GROUP 00 

− How 

to Cope with Intermittent Malfunction 

P.00-15

.)

STEP 13. Check whether the DTC is reset.
Q: Is DTC C2114 or C2115 set?

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

DTC C123A: Abnormality in sensor calibration

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.

• 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, 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 stores the calibrated value of the G and yaw rate 
sensor, steering wheel sensor, and master cylinder pressure 
sensor.

.

DTC SET CONDITIONS

This diagnostic trouble code is set when the calibrated value for 
each sensor stored in ASC-ECU is abnormal.

• Abnormality of G and yaw rate sensor neutral position

• Abnormality of steering wheel sensor neutral position

• Abnormality of master cylinder pressure sensor neutral 

position

.

PROBABLE CAUSES

• Accidental shutdown of power supply during storing opera-

tion of calibrated value

• ASC-ECU malfunction

• External noise interference