Mitsubishi Lancer Evolution X. Manual - part 180

DIAGNOSIS

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ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-185

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-287

, 

P.35C-289

, 

P.35C-294

, and 

P.35C-295

.)

.

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-15

.) 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.

DIAGNOSIS

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ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-186

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).

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-298

.) 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.

DIAGNOSIS

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ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-187

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

DTC C2115: Abnormality in G and yaw rate sensor operation voltage (High 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-287

.)

• 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-287

, 

P.35C-289

, 

P.35C-294

, and 

P.35C-295

.)

.

G and Yaw Rate Sensor Circuit

ASC-ECU

G AND YAW 
RATE SENSOR

AC708948

Connector: A-05

A-05 (B)

AB

AC708951AG

C-38 (B)

Connector: C-38

DIAGNOSIS

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ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-188

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 local CAN bus lines.

.

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 − 

CAN Bus Diagnostics table 

P.54C-15

). On 

completion, go to Step 2.

STEP 2. Check for diagnostic trouble codes of other 
systems
Check if DTC 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-212

.) Then go to 

Step 3.

NO :  Go to Step 3.