Mitsubishi Lancer (4A9 engine). Manual - part 82

ON-VEHICLE SERVICE

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-181

Judgment Table

Display on 
M.U.T.-III

Operation

Test result

Judgme
nt

Cause

Measure

01 FL wheel 
ABS drive
02 FR wheel 
ABS drive
03 RL wheel 
ABS drive
04 RR wheel 
ABS drive

• Depress the brake 

pedal to lock the 
wheel.

• Select the vehicle 

to be inspected 
using M.U.T.-III, 
perform the 
actuator test.

• Rotate the selected 

wheel by hands to 
confirm the braking 
force.

Braking force 
decreases for 3 
seconds from 
the lock status.

Normal

−

−

The wheel 
does not lock 
even if the 
brake pedal is 
depressed.

Error

Clogged brake line 
other than hydraulic 
unit

Check and 
clean the brake 
line.

Clogged hydraulic 
circuit in the hydraulic 
unit

Replace the 
hydraulic unit 
assembly.

Braking force 
does not 
decrease.

Faulty routing of 
hydraulic unit brake 
tube

Route the 
brake tube 
correctly.

Malfunction of 
hydraulic unit solenoid 
valve operation

Replace the 
hydraulic unit 
assembly.

05 FL wheel 
TCL drive
06 FR wheel 
TCL drive
07 RL wheel 
TCL drive
08 RR wheel 
TCL drive

• Select the vehicle 

to be inspected 
using M.U.T.-III, 
perform the 
actuator test.

• Rotate the selected 

wheel by hands to 
confirm the braking 
force.

Lock condition 
occurs for 3 
seconds from 
the status 
without braking 
force.

Normal

−

−

The wheel 
does not lock.

Error

• Faulty routing of 

hydraulic unit brake 
tube

• Clogged brake line 

other than hydraulic 
unit

Check and 
clean the brake 
line.

Clogged hydraulic 
circuit in the hydraulic 
unit

Replace the 
hydraulic unit 
assembly.

7. After the inspection, turn the ignition switch to the 

LOCK (OFF) position, and then disconnect 
M.U.T.-III.

Hydraulic unit installation adjustment
Refer to 

P.35C-185

.

1. Operate the pre-removal steps for the hydraulic 

unit.

2. Remove all brake tubes.
3. Remove the protector.
4. Loosen the mounting bolt and nut of the hydraulic 

unit bracket.

5. Install all brake tubes temporarily.

6. Shake hydraulic unit to all directions with both 

hands to make the hydraulic unit bracket insulator 
fit with the unit.

7. Install the the hydraulic unit bracket with mounting 

bolt and nut not to load the brake tube.

8. Install the protector.
9. Install all brake tubes securely.

NOTE: Install the flare nut taking care not to let 
the brake tube turn together.

10.Operate the post-installation steps of the 

hydraulic unit.

ON-VEHICLE SERVICE

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-182

MEASURES FOR DISCHARGED 
BATTERY

M1355006200102

CAUTION

Because the vehicle posture when applying the 
brakes becomes unstable, do not leave ABS/ASC 
disabled (for example, ASC-ECU connector dis-
connection).
When starting the engine using a booster cable with 
the battery fully discharged, if you begin driving the 
vehicle before the battery is fully charged, the engine 
misfire may occur and you cannot start the vehicle. 
This is because ABS/ASC consumes more electric 
current to perform the self-check. In this case, 
charge the battery fully.

ALL SENSOR CALIBRATION (G AND YAW 
RATE SENSOR, STEERING WHEEL 
SENSOR, BRAKE FLUID PRESSURE 
SENSOR)

M1357003900012

CAUTION

Before carrying out the calibration, check that 
the diagnosis code related to the steering wheel 
sensor, G and yaw rate sensor, or brake fluid 
pressure sensor is not set.

CAUTION

When the next operation has been completed, 
carry out the calibration to make ASC-ECU learn 
the neutral point of the steering wheel sensor, G 
and yaw rate sensor, and brake fluid pressure 
sensor.

• ASC-ECU replacement

CAUTION

Carry out the calibration under the following con-
ditions.

• The vehicle has one occupant (driver) only.
• Turn the steering wheel to set the wheels in 

the straight-ahead positions. 

• The brake pedal is not depressed. (The stop 

lamp switch is OFF.)

1. Park the vehicle on a level surface.

CAUTION

Before connecting or disconnecting M.U.T.-III, 
always turn the ignition switch to the LOCK 
(OFF) position.
2. Before setting M.U.T.-III, turn the ignition key to 

the LOCK (OFF) position.

3. Turn the ignition switch to the ON position.

4. Select "ABS/ASC/ASTC."
5. Select "Special function."
6. Select "Sensor calibration."
7. Select "all sensor calibration."
8. Before removing M.U.T.-III from the vehicle, turn 

the ignition key to the LOCK (OFF) position.

G AND YAW RATE SENSOR 
CALIBRATION

M1355009300313

CAUTION

Before performing calibration, check that the G 
and yaw rate sensor-related diagnosis code is 
not set.

CAUTION

After the next operation has been completed, 
carry out the calibration to make ASC-ECU learn 
the neutral point of the G and yaw rate sensor.

• G and yaw rate sensor replacement
• ASC-ECU replacement

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

CAUTION

Before connecting or disconnecting M.U.T.-III, 
always turn the ignition switch to the LOCK 
(OFF) position.
3. Check that the ignition key is in the LOCK (OFF) 

position, and then set M.U.T.-III.

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

ASTC/WSS" in the "System table," and then click 
the "OK" button.

7. In the "ABS/ASC/ASTC/WSS" field, select 

"Special function".

8. Among the selected items, select "Learn lateral G-

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

9. "Learn lateral G-sensor neutral position: Are you 

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

10."Execute command: Executed" is displayed. 

Then, press the "OK" button.

11.The neutral point is learned.
12.Turn the ignition key to the LOCK (OFF) position, 

and remove M.U.T.-III from the vehicle.

ON-VEHICLE SERVICE

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-183

STEERING WHEEL SENSOR 
CALIBRATION

M1355009200338

CAUTION

After the next operation has been completed, 
carry out the following two operations:

• Alignment adjustment <Front>
• Steering wheel sensor (column switch assem-

bly) replacement, removal, installation

• ASC-ECU replacement

1. Update the neutral position stored in the 

steering wheel sensor.

2. Reset the calibrated value of the steering 

angle stored in ASC-ECU.

CAUTION

• Before performing the calibration, check if the 

steering wheel sensor-related diagnosis code 
is set in ASC-ECU.

• When the diagnosis code other than C121A is 

set, carry out the inspection according to 
each troubleshooting procedure.

Park the vehicle on a level surface with tyres and 

steering wheel positioned in a straight ahead 
direction.

1. Turn the ignition switch to the ON position.
2. Turn the ignition key to the LOCK (OFF) position.

CAUTION

Before connecting or disconnecting M.U.T.-III, 
always turn the ignition switch to the LOCK 
(OFF) position.
3. Check that the ignition key is in the LOCK (OFF) 

position, and then set M.U.T.-III.

4. Turn the ignition switch to the ON position.
5. On the Menu, select "System selection."
6. In "System table" of "System selection," select 

"Steering angle sensor," and then press the "OK" 
button.

7. In "Steering angle sensor," select "Special 

function."

8. In "Special function," select "Learn neutral 

position of steering angle sensor."
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 initialise the 
steering angle sensor neutral position." is dis-
played. If it is okay, press the "OK" button.

9. In "Learn neutral position of steering angle 

sensor," "Initialise 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, "Initialise neutral 
position of steering angle sensor: Do you want to 
execute? Note: The diagnosis code will be 
erased." is displayed. Then, press the "OK" but-
ton.

10."Initialise neutral position of steering angle 

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

11.Press the "OK" button.
12."Learn neutral position of steering angle sensor: 

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

13."Learn neutral position of steering angle sensor: 

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

14.After turning the ignition switch to LOCK (OFF) 

position, turn it to the ON position again.

15.On the Menu, select "System selection."
16.On the "System selection," select "ABS/ASC/

ASTC/WSS" in the "System table," and then click 
the "OK" button.

17. In the "ABS/ASC/ASTC/WSS" field, select 

"Special function".

18.In the "Special function," select "Learn sensor 

neutral position."

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

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

20."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.

21."Execute command: Executed" is displayed. 

Then, press the "OK" button.

22.In the "ABS/ASC/ASTC/WSS" field, select "Self 

diagnosis." If diagnosis code of "C2205 SAS 
internal error (past failure)" is set, erase it.

23.The neutral point is learned.
24.Turn the ignition key to the LOCK (OFF) position, 

and remove M.U.T.-III from the vehicle.

ASC OFF SWITCH

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-184

BRAKE FLUID PRESSURE SENSOR 
CALIBRATION

M1355024100048

CAUTION

Before performing calibration, check that the 
brake fluid pressure sensor-related diagnosis 
code is not set.

CAUTION

After the next operation has been completed, 
carry out the calibration to make ASC-ECU learn 
the neutral position of the brake fluid pressure 
sensor.

• When the troubleshooting for code No. C123A 

is carried out

• Brake fluid pressure sensor replacement
• ASC-ECU replacement

CAUTION

Always perform the calibration with the brake 
pedal released (stop lamp switch is turned off).
1. Park the vehicle on a level surface.

CAUTION

Before connecting or disconnecting M.U.T.-III, 
always turn the ignition switch to the LOCK 
(OFF) position.
2. Before setting M.U.T.-III, turn the ignition key to 

the LOCK (OFF) position.

3. Turn the ignition switch to the ON position.
4. Select "ABS/ASC/ASTC."
5. Select "Special function."
6. Select "Sensor calibration."
7. Select "M/C pressure sensor calibration."
8. Before removing M.U.T.-III from the vehicle, turn 

the ignition key to the LOCK (OFF) position.

ASC OFF SWITCH

REMOVAL AND INSTALLATION

M1355020100303

ACA01061 AB

3

1

2

Removal steps 

1.

Instrument panel lower (Refer to 
GROUP 52A, Instrument panel 
lower ).

2.

ASC OFF switch <except AS&G>

3.

ASG OFF & ASC OFF switch 
<AS&G>

Removal steps (Continued)