Mitsubishi Lancer Evolution X. Manual - part 207

ON-VEHICLE SERVICE

TSB Revision

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-293

NOTE: When the neutral position of steering angle sensor 
has been learned, "Neutral position learned already: in order 
to relearn the neutral position, press the OK button to initial-
ize the steering angle sensor neutral position." is displayed. 
If it is okay, press the "OK" button.

6. In "Learn neutral position of steering angle sensor," 

"Initialize neutral position of steering angle sensor" is 
selected, thus press the "OK" button.
NOTE: When the neutral position of steering angle sensor 
has been learned, "Initialize neutral position of steering 
angle sensor: Do you want to execute? Note: The diagnostic 
trouble code will be erased." is displayed. Then, press the 
"OK" button.

7. "Initialize neutral position of steering angle sensor: 

Completed" is displayed. Then, press the "OK" button.

8. Press the "OK" button.
9. "Learn neutral position of steering angle sensor: Do you 

want to execute? Note: Execute after the tires and steering 
wheel are aligned in a straight ahead direction." is displayed. 
Then, press the "OK" button.

10."Learn neutral position of steering angle sensor: Completed" 

is displayed. Then, press the "OK" button.

11.After turning the ignition switch to LOCK (OFF) position, turn 

it to the ON position again.

12.On the Menu, select "System selection."
13.On the "System selection," select "ACD/AYC" in the 

"System table," and then click the "OK" button.

14. In the "ACD/AYC" field, select "Special function".
15.In the "Special function," select "Learn sensor neutral 

position."

16.In "Learn sensor neutral position," select "Learn neutral 

position of steering angle sensor," and then press the "OK" 
button.

17."Learn neutral position of steering angle sensor: Are you 

sure to execute the selected item? Note: Check the 
execution conditions." is displayed. Then, press the "OK" 
button.

18."Execute command: Executed" is displayed. Then, press 

the "OK" button.

19.In the "ACD/AYC" field, select "Self diagnosis." If diagnostic 

trouble code of "U1428 G and yaw rate sensor data error 
(past failure)" is set, erase it.

20.The neutral point is learned.
21.Turn the ignition key to the LOCK (OFF) position, and 

remove scan tool from the vehicle.

ON-VEHICLE SERVICE

TSB Revision

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-294

MASTER CYLINDER BRAKE FLUID PRESSURE 
SENSOR CALIBRATION

M1355024500013

CAUTION

• Before performing the calibration, check that the wheel 

cylinder brake fluid pressure sensor-related diagnostic 
trouble code is not set.

• Always perform the calibration with the brake pedal 

released (stoplight switch is turned off).

• After the operation below is completed, perform the cal-

ibration to make ASC-ECU to learn the neutral point of 
the wheel cylinder brake fluid pressure sensor.

1. Troubleshooting for diagnostic trouble code No. 

C123A

2. ASC-ECU replacement

1. Park the vehicle on a level surface.
2. Turn the ignition key to the ON position.
3. Turn the ignition key to the LOCK (OFF) position.

CAUTION

Before connecting or disconnecting scan tool MB991958, 
always turn the ignition switch to the LOCK (OFF) position.
4. Check that the ignition key is in the LOCK (OFF) position, 

and then set scan tool MB991958.

5. Turn the ignition switch to the ON position.
6. On the Menu, select "System selection."
7. On the "System selection," select "ABS/ASC/ASTC/WSS" in 

the system list, and then click the "OK" button.

8. Select "Special function" in the "ABS/ASC/ASTC/WSS" field.
9. In the "Special function," select "Learn sensor neutral 

position."

10.Among the selected items, select "Learn M/C pressure 

sensor neutral position," and then press the "OK" button.

11.When a message "Learn M/C pressure sensor neutral 

position: Are you sure to execute the selected item? 
Caution: Check the execution conditions" is displayed, press 
the "OK" button.

12.When a message "Command execution: Command has 

been executed" is displayed, press the "OK" button.

13.The neutral point is learned.
14.Turn the ignition key to the LOCK (OFF) position, and then 

remove the scan tool from the vehicle.

ON-VEHICLE SERVICE

TSB Revision

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-295

Calibration of cut valve and inlet valve

M1355024700017

CAUTION

• Before the calibration work of the cut valve and inlet 

valve, check that no diagnostic trouble code is set 
relating to the cut valve, inlet valve, motor system, 
power supply system, or ECU system.

• Always perform the calibration of cut valve and inlet 

valve with the brake pedal released (stoplight switch is 
turned off).

• If any diagnostic trouble code other than No. C2002 is 

also set, always perform the diagnosis of the diagnos-
tic trouble code other than No. C2002 first.

• After the replacement of ASC-ECU, the calibration of 

cut valve and inlet valve must be performed with the 
new ASC-ECU.

• When the cut valve calibration is performed, the cali-

bration of master cylinder fluid pressure sensor is also 
executed at the same time.

• When the cut valve calibration is not completed, the 

inlet valve calibration cannot be performed.

• After the completion of following works, always per-

form the calibration of cut valve and inlet valve.

1. Diagnosis for the diagnostic trouble code No. C2002 

is performed.

2. ASC-ECU replacement

1. Park the vehicle on a level surface.
2. Turn the ignition key to the ON position.
3. Turn the ignition key to the LOCK (OFF) position.

CAUTION

Before connecting or disconnecting scan tool, always turn 
the ignition switch to the LOCK (OFF) position.
4. Check that the ignition key is in the LOCK (OFF) position, 

and then set scan tool.

5. Turn the ignition switch to the ON position.
6. On the Menu, select "System selection."
7. On the "System selection," select "ABS/ASC/ASTC/WSS" in 

the system list, and then click the "OK" button.

8. Select "Special function" in the "ABS/ASC/ASTC/WSS" field.
9. In the "Special function," select "Learn valve fluid pressure."
10.Among the selected items, select "Cut valve fluid pressure," 

and then press the "OK" button.

11.When a message "Cut valve fluid pressure: Are you sure to 

execute the selected item? Caution: Check the execution 
conditions" is displayed, press the "OK" button.

12.When a message "Command execution: Command has 

been executed" is displayed, press the "OK" button.

13.Check that the message changes from "Under execution" to 

"Complete."
NOTE: The cut valve fluid pressure learning requires 
approximately 20 seconds.

ASC OFF SWITCH

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ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-296

14.Among the selected items, select "Inlet valve fluid 

pressure," and then press the "OK" button.

15.When a message "Inlet valve fluid pressure: Are you sure to 

execute the selected item? Caution: Check the execution 
conditions" is displayed, press the "OK" button.

16.When a message "Command execution: Command has 

been executed" is displayed, press the "OK" button.

17.Check that the message changes from "Under execution" to 

"Complete."
NOTE: The inlet valve fluid pressure learning requires 
approximately 20 seconds.

18.The valve fluid pressure learning is complete.
19.Turn the ignition key to the LOCK (OFF) position, and then 

remove the scan tool from the vehicle.

ASC OFF SWITCH

REMOVAL AND INSTALLATION

M1355020100109

AC708758AB

1

3

2

4

Removal steps 

1.

Instrument panel lower assembly 
(Refer to GROUP 52A − 
Instrumental Lower Panel 

P.52A-9

.)

2.

ASC OFF switch connector

3.

Instrument panel lower

4.

ASC OFF switch

Removal steps (Continued)