Mitsubishi Evolution X. Manual - part 801

DIAGNOSIS

TSB Revision

ACTIVE SKID CONTROL SYSTEM (ASC)

35C-211

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, 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 

P.35C-266

, 

P.35C-267

, 

P.35C-268

, and 

P.35C-269

.)

.

CIRCUIT OPERATION

The G and yaw rate sensor outputs the signal to ASC-ECU and 
S-AWC-ECU via the special CAN bus lines.

.

DTC SET CONDITIONS

This diagnostic trouble code is set when ASC-ECU cannot 
receive the signal sent from the G and yaw rate sensor.

.

PROBABLE CAUSES

• Wiring harness or connector failure in special CAN bus lines 

between ASC-ECU and G and yaw rate sensor

• 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 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.

DIAGNOSIS

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ACTIVE SKID CONTROL SYSTEM (ASC)

35C-212

STEP 2. DTC recheck after repairing the CAN bus line
Q: Is DTC U1003 set?

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

STEP 3. Connector check: A-05 ASC-ECU connector, C-46 
S-AWC-ECU connector, C-47 intermediate connector, C-50 
joint connector
Q: Is the check result normal?

YES : Go to Step 4.
NO :  Repair the connector, and then go to Step 7.

STEP 4. Wiring harness check between A-05 ASC-ECU 
connector terminal No. 18 and C-38 G and yaw rate sensor 
connector terminal No. 2, between A-05 ASC-ECU 
connector terminal No. 19 and C-38 G and yaw rate sensor 
connector terminal No. 3, between C-46 S-AWC-ECU 
connector terminal No. 9 and C-38 G and yaw rate sensor 
connector terminal No. 2, between C-46 S-AWC-ECU 
connector terminal No. 10 and C-38 G and yaw rate sensor 
connector terminal No. 3

• Open or short circuit check of communication circuit

Q: Is the check result normal?

YES : Go to Step 5.
NO :  Repair the wiring harness, and then go to Step 7.

STEP 5. Check whether the DTC is reset.
Q: Is DTC U1003 set?

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

P.35C-278

.) Then go to Step 6.

NO :  Intermittent malfunction. (Refer to GROUP 00 

− How 

to Cope with Intermittent Malfunction 

P.00-15

.)

STEP 6. Check whether the DTC is reset.
Q: Is DTC U1003 set?

YES : Replace the hydraulic unit (incorporates in 

ASC-ECU).(Refer to 

P.35C-272

.) Then go to Step 7.

NO :  The procedure is complete.

STEP 7. Check whether the DTC is reset.
Q: Is DTC U1003 set?

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

DIAGNOSIS

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ACTIVE SKID CONTROL SYSTEM (ASC)

35C-213

DTC U1415: Variant coding not completed

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 diagnostic trouble code No. U1415 is set in 

ASC-ECU, the diagnostic trouble code may also be set 
in ETACS-ECU. When the diagnostic trouble code is set 
in ETACS-ECU, perform the diagnosis of the diagnostic 
trouble code for ETACS-ECU first.

• 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 

P.35C-266

, 

P.35C-267

, 

P.35C-268

, and 

P.35C-269

.)

.

CIRCUIT OPERATION

ASC-ECU receives the vehicle information stored in the 
ETACS-ECU via CAN bus lines.

.

DTC SET CONDITIONS

This diagnostic trouble code is set when the variant coding for 
ETACS-ECU has not been completed.

.

PROBABLE CAUSES

• Variant coding for ETACS-ECU has not been implemented.

• 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 5.

DIAGNOSIS

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ACTIVE SKID CONTROL SYSTEM (ASC)

35C-214

STEP 2. Scan tool diagnostic trouble code for other 
systems
Use scan tool to check that the diagnostic trouble code B222C 
is set in the ETACS-ECU.
Q: Is any DTC set?

YES : Perform troubleshooting for the diagnostic trouble 

code that is set. Then go to Step 4.

NO :  Go to Step 3.

STEP 3. Check for diagnostic trouble codes of other 
systems
Q: Is DTC U1417 set?

YES : Perform the troubleshooting for diagnostic trouble 

code No. U1417.(Refer to 

P.35C-215

.)

NO :  Go to Step 4.

STEP 4. Check whether the DTC is reset.
(1) Ignition switch "LOCK" (OFF)
(2) Ignition switch "ON"
(3) Check that the ABS warning light is extinguished.
Q: Is DTC U1415 set?

YES : Replace the hydraulic unit (incorporates in 

ASC-ECU).(Refer to 

P.35C-272

.) Then go to Step 5.

NO :  Intermittent malfunction. (Refer to GROUP 00 

− How 

to Cope with Intermittent Malfunction 

P.00-15

.)

STEP 5. Check whether the DTC is reset.
(1) Ignition switch "LOCK" (OFF)
(2) Ignition switch "ON"
(3) Check that the ABS warning light is extinguished.
Q: Is DTC U1415 set?

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