Mitsubishi Evolution X. Manual - part 792

DIAGNOSIS

TSB Revision

ACTIVE SKID CONTROL SYSTEM (ASC)

35C-175

• Abnormality is detected by the self-diagnosis of the G and 

yaw rate sensor.

• Output value of the G and yaw rate sensor is not within the 

standard value range.

NOTE: This diagnostic trouble code may be set when G and 
yaw rate sensor is put on the turntable turning at high speed.

.

PROBABLE CAUSES

• Improper installation of the G and yaw rate sensor

• 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. Check whether the DTC is reset.
Q: Is DTC C2204 set?

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

DIAGNOSIS

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ACTIVE SKID CONTROL SYSTEM (ASC)

35C-176

STEP 4. 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 : 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 7.

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 6.

STEP 6. Check whether the DTC is reset.
Q: Is DTC C2204 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 C2204 set?

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

DTC C2111: Brake fluid pressure sensor power supply circuit (low input)

 

DTC C2112: Brake fluid pressure sensor power supply circuit (high input)

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

.)

.

DIAGNOSIS

TSB Revision

ACTIVE SKID CONTROL SYSTEM (ASC)

35C-177

CIRCUIT OPERATION

When the brake pedal is depressed, the master cylinder pres-
sure sensor integrated in the hydraulic unit detects the brake 
fluid pressure applied from the master cylinder. At the same 
time, it converts the pressure value into voltage signal, and out-
puts the signal.

.

DTC SET CONDITIONS

If the voltage supplied to the master cylinder pressure sensor is 
outside the standard value range, these diagnostic trouble 
codes are set.

.

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

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 C2111 or C2112 set?

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

STEP 3. Battery check
Refer to GROUP 54A 

− Battery Test 

P.54A-9

.

Q: Is the battery in good condition?

YES : Go to Step 4.
NO :  Charge or replace the battery.

STEP 4. Charging system check
Refer to GROUP 16 

− Charging System 

P.16-7

.

Q: Is the charging system in good condition?

YES : Go to Step 5.
NO :  Repair or replace the charging system component(s).

DIAGNOSIS

TSB Revision

ACTIVE SKID CONTROL SYSTEM (ASC)

35C-178

STEP 5. Check whether the DTC is reset.
Q: Is DTC C2111 or C2112 set?

YES : Replace the hydraulic unit (incorporates in 

ASC-ECU).(Refer to 

P.35C-272

.) 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 C2111 or C2112 set?

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

DTC C2114: Abnormality in G and yaw rate sensor operation voltage 

 

DTC C2115: Abnormality in G and yaw rate sensor operation voltage

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 supplies power to the G and yaw rate sensor at 

the terminal No. 1.

• The G and yaw rate sensor outputs the signal to ASC-ECU 

via the special CAN bus lines.

.

AC708948

Connector: A-05

A-05 (B)

AB

AC708951AG

C-38 (B)

Connector: C-38