MITSUBISHI COLT 2006 Service Repair Manual

GROUP 35C
ACTIVE STABILITY
CONTROL SYSTEM
(ASC)
CONTENTS
GENERAL . . . . . . . . . . . . . . . . . . . . .35C-2
CONSTRUCTION DIAGRAM. . . . . . .35C-5
SENSOR . . . . . . . . . . . . . . . . . . . . . . . . . . . 35C-5
ACTUATOR . . . . . . . . . . . . . . . . . . . . . . . . . 35C-6
ASC-ECU . . . . . . . . . . . . . . . . . . . . . . . . . . 35C-7
DESCRIPTION OF CONSTRUCTION
AND OPERATION . . . . . . . . . . . . . . .35C-17

GENERAL
ACTIVE STABILITY CONTROL SYSTEM (ASC)35C-2
GENERAL
M2357000200040
The active stability control system (ASC) has been
installed to the M/T vehicle.
•The active stability control system (ASC) has the
stability control and the traction control (TCL)
functions. By the integrated control with the
anti-lock brake system, the system stabilises the
vehicle attitude and at the same time secures the
driving force.
•When the stability control function determines
that the vehicle is in a dangerous condition, it
reduces the engine output and applies brake
force to four wheels independently to control the
vehicle behaviour, avoiding the critical state.
•The traction control (TCL) function prevents the
driving wheel slip on a slippery road surface,
ensuring easy startup, and at the same time,
secures proper driving force and improves steer
-
ing performance during cornering acceleration.
•Fail-safe function assures the security.
•Serviceability improvement
•For wiring harness saving and secure data com-
munication, the CAN* communication has been
adopted as a tool of communication with another
ECU.
NOTE: .
•*For more information about CAN (Controller
Area Network), refer to GROUP 54C
P.54C-2.
•ABS and ASC are controlled by ASC-ECU.
CONSTRUCTION DIAGRAM
AC600849AB
1 12
2
3
46
5
7
8
9, 10, 17
14
12
11
13
15
16

ComponentNo.Function
SensorWheel speed sensor1Sends alternating current signals at frequencies which are
proportional to the rotation speeds of each wheel to the
active stability control system-ECU
Magnetic encoder for wheel
speed detection2The wheel speed sensor is a pulse generator. When the
magnetic encoder for wheel speed detection (a plate on
which north and south pole sides of the magnets are
arranged alternately) rotates, it outputs frequency pulse
signal in proportion to each wheel speed.
Stop lamp switch3Sends a signal to the active stability control system-ECU
to indicate whether the brake pedal is depressed or not.
Parking brake switch4Outputs the signal indicating whether the parking brake
lever is pulled or not to ASC-ECU.
Brake fluid level switch5Outputs the signal indicating whether the brake fluid is
filled to the lowest limit level or not to ASC-ECU.
G and yaw rate sensor6Detects the lateral acceleration and the yaw rate for the
vehicle. Then it sends a signal through the CAN bus line to
the active stability control system-ECU.
Steering wheel sensor7Detects the steering wheel angle, and sends a signal to
the active stability control system-ECU through the CAN
bus line.
ASC OFF switch8Outputs the ASC ON/OFF signal to ASC-ECU.
Pressure sensor9Is incorporated in the hydraulic unit, and informs the active
stability control system-ECU of the brake fluid pressure in
the master cylinder.
ActuatorHydraulic unit10Drives the solenoid valves and pump motor according to
signals from the ABS/active stability control system-ECU in
order to control the brake hydraulic pressure for each wheel.
ABS warning lamp11Illuminates in response to signals from the active stability
control system-ECU when a problem develops in the
system.
Brake warning lamp12Illuminates in response to signals from the active stability
control system-ECU when a problem develops in the EBD
system or the brake fluid level is low.
Active stability control system
(ASC) indicator lamp 13Receives a signal from the active stability control
system-ECU, and flashes to inform the driver that the
system is operating, or illuminates to inform the driver of
system shutdown.
ASC OFF indicator lamp14Informs the driver of the ASC shutdown by illuminating
with the signal from ASC-ECU.
Diagnosis connector15Sets the diagnosis codes and allows communication with
the M.U.T.-III.
Engine-ECU16Receives a signal from the active stability control
system-ECU to control the engine output.
Anti-skid Brake/Active Stability Control
System control unit (ABS/active stability
control system-ECU)17Controls actuators (described above) based on the signals
coming from each sensor.
Controls the self-diagnostics and fail-safe functions.
Controls the diagnostic function (M.U.T.-III compatible).
GENERAL
ACTIVE STABILITY CONTROL SYSTEM (ASC)35C-3

GENERAL
ACTIVE STABILITY CONTROL SYSTEM (ASC)35C-4
SCHEMATIC DIAGRAM
AC600637AC
Combination meter
ABS warning lamp 
· Brake warning lamp
· Active stability control indicator lamp
· Active stability control OFF indicator lamp
Diagnosis
Connector
Control solenoid valve (FR) OUT
Control solenoid valve (FR) IN
Control solenoid valve (FL) OUT
Control solenoid valve (FL) IN
Control solenoid valve (RR) OUT
Control solenoid valve (RR) IN
Control solenoid valve (RL) OUT
Control solenoid valve (RL) IN Suction valve (FR)
Suction valve (FL)
Cut valve (FR)
Cut valve (FL) Pump motor
Active stability
control system-ECU
Front-left wheel speed sensor
Rear-left wheel speed sensor
Front-right wheel speed sensor Rear-right wheel speed sensor
Master cylinder pressure sensor Stop lamp switch
Parking brake switch
Brake fluid level switch
Power supply to active stability
control system-ECU Steering wheel sensor
G and yaw rate sensor
Engine-ECU
Steering wheel sensor
Front-right wheel (FR)
Wheel
speed
sensor
Engine-ECU
G and yaw rate sensor
Parking
brake
switch Rear-right wheel (RR)
Wheel
speed
sensor
Stop lamp switch
Hydraulic
unit Wheel speed
sensor Rear-left
wheel (RL)
Wheel speed
sensor
Front-left wheel (FL)
Note
: CAN-bus line

CONSTRUCTION DIAGRAM
ACTIVE STABILITY CONTROL SYSTEM (ASC)35C-5
CONSTRUCTION DIAGRAM
SENSORM2357000300036
G AND YAW RATE SENSOR
AC600804ACG and yaw rate sensor
Parking brake lever
This sens or , inst alled u nder th e ce ntre conso l e,
detect
s the yaw rate a nd lateral accelera tion of the
vehicle
.
STEERING WHEEL SENSOR
AC600803ACSteering wheel sensor
This sens or , a t t a ched to the column switch, det ect s
the rot
a tional angle of the stee ring whe e l.
ASC OFF SWITCH
AC600923ABASC OFF switch
Th is swit ch is at t a che d on the inst rument p a nel to the
right side
of the driver's seat. The ASC system ca n
be turn
ed OFF by pressing this ASC OFF switch for
3 seconds when t
he ig nition switch is ON. By pre s s
-
ing the switch a gain, the system can be turned ON.
NOTE: .
•Whe n the ASC syste m is turn ed OFF , the ASC
OFF ind
i ca tor illuminat es.
•If the ASC OFF switch is presse d for 15 se cond s
or
more , the ope ratio nal error prevention function
activates, and th
e ASC system can not be turned
OFF until the
ign i tion switch is turn ed to t he ON
position ag
ain.
ASC OFF switch ope ra tion and system operation
ASC OFF switch controlTCL functionStability control function
ON (ASC OFF indicator goes out.)EnabledEnabled
OFF (ASC OFF indicator
illuminates.)ProhibitedProhibited
NOTE: The ASC function st a r t s the co ntrol when t he
vehicle
spe ed is 10 km/h or mo re.

CONSTRUCTION DIAGRAM
ACTIVE STABILITY CONTROL SYSTEM (ASC)35C-6
ACTUATOR
M2357000400033
HYDRAULIC UNIT
The hydraulic unit incorporates the ABS control and
ASC control. The cut valve, pressure relief valve,
suction valve, suction damper, and pressure sensor
have been added to the unit for the ASC control.
NOTE: For the internal hydraulic circuit of the
hydraulic unit, refer to
P.35C-17.
ASC INDICATOR LAMP, ASC OFF
INDICATOR LAMP
The ASC system illuminates or flashes the ASC indi-
cator lamp or ASC OFF indicator lamp in the follow-
ing operation patterns, and informs the driver of the
ASC system status.
ASC indicator lamp
•Flashes in 3 Hz interval during the stability con-
trol.
•Flashes in 3 Hz interval during the TCL control.
•Turns ON when the system malfunction occurs.
ASC OFF indicator lamp
•Illuminates when the ASC system is not acti-
vated.
ASC indicator lamp, ASC OFF indicator lamp illumination and flashing patterns
StateASC indicator lampASC OFF indicator lamp
NormalValve checkIlluminates for approx. 3
seconds after the ignition
switch is turned ON.Illuminates for approx. 3
seconds after the ignition
switch is turned ON.
Normal−−
When the stability control is enabledFlashing (3 Hz)−
TCL operatedFlashing (3 Hz)−
When the ASC control is turned
OFF by the ASC OFF switch−Illuminates
Abnorma
lStability control malfunctionIlluminatesIlluminates
TCL malfunctionIlluminatesIlluminates
M.U.T.-III
connecti
on−IlluminatesIlluminates

CONSTRUCTION DIAGRAM
ACTIVE STABILITY CONTROL SYSTEM (ASC)35C-7
ASC-ECU
M2357000100043
ABS-ECU and ASC-ECU are integrated in this ECU.
SYSTEM CONFIGURATION
The hydraulic unit of the ASC system employs the
automatic pressurisation function for stability and
TCL control. The system also incorporates G and
yaw rate sensor, steering wheel sensor, and pres
-
sure sensor (integrated with hydraulic unit).
CONTROL DESCRIPTION
ASC-ECU detects vehicle movement based on infor-
mation from various sensors and calculates a model
of ideal vehicle movement. ASC-ECU compares the
actual vehicle movement with the ideal vehicle
model, and manages the brak e of the specific wheel
so that the actual vehicle movement gets close to the
ideal vehicle mode. It also controls the understeer or
oversteer condition by creating the yaw moment
(rotating direction force) in the vehicle.
Stability control
The stability control manages the vehicle attitude by
creating a yaw moment (rotating direction force) from
altering the balance between the cornering force and
each wheel’s braking mechanism.
Example of stability control operation
AC313359AB
Creating a rotational moment Creating a restorative moment
Braking force
increase
Braking force
increase
For example, on a slippe ry surface, if t he ve hicle
tends to be
under-steered con t rary t o the d r ive r ’ s
inten
t ion, a yaw mome nt (a ro t a tional mo ment) is
create
d to re strain the u nder-steering by increasing
the rear
-inside b r aking force. On the other ha nd,
whe
n the vehicle tends to b e ove r stee red, a yaw moment (a re storat ive moment) is crea ted to re strain
the overst eering by incre a sing the front-ou t side
wh eel b r aking force. Furt hermo re, when it is dete r
-
mined tha t the vehicle is o v er-speeding, safe a nd
st
able corn ering is e nabled by decelerat ion f r om
reducing t
he eng ine o u tput.

CONSTRUCTION DIAGRAM
ACTIVE STABILITY CONTROL SYSTEM (ASC)35C-8
EXAMPLE OF THE EFFECT OF CONTROL
AC204504
AC204505
AC204506AC204507AB
Restraining under-steering Restraining over-steering
Avoiding under-steering Avoiding wheel spin
Improving ABS performance
Stable vehicle attitude
after avoiding obstacles
Example of TCL control
When th e driving wheel slip s (ex. during drivin g on
low
µ road), TCL send s the engine out put red u ction
sign
al to the en gine ECU in order to prevent th e driv
-
ing f o r c e loss cau s e d by t he dr iving whe e l slip . A t t h e
same time, TCL a
pplies th e brake to t he slipp i ng
driving whe
e l so that the drivin g force is applied to
t
he non-slipping driving wheel, which co ntrols the slip
o
f th e drivi ng wheel, securin g the prop er d r iving f o rce
and increa
sed steering fo rce.
Fail-safe and diagnostic functions
ASC-ECU constantly mo nitors the input and ou tput
sign
als. If an error is det ected in th e syste m ,
ASC-ECU send
s a f a il sign al a nd the correspond ing
indicato
r lamp is illuminate d or blinks. V a riou s con
-
trols are proc essed depen ding on the cause of mal-
functi on a s shown below . ASC-ECU has the
follo
wing fu nctions for easier system checks.
•Diagnosis code set
•Service dat a outp u t
•Actuator te st
All the above it ems can be diagnosed using
M.U.T
. -III.

CONSTRUCTION DIAGRAM
ACTIVE STABILITY CONTROL SYSTEM (ASC)35C-9
FAIL-SAFE FUNCTION
Diagnosis
code No.ItemABSEBDTCLASC
Engine
controlBrake
controlEngine
controlBrake
control
C1200Wheel speed sensor (FR)
system (open circuit or
short to earth or power
supply)ProhibitedEnabled
(Prohibited
when three
or more
wheels
have fault.)ProhibitedProhibitedProhibitedProhibited
C1205Wheel speed sensor (FL)
system (open circuit or
short to earth or power
supply)
C1210Wheel speed sensor (RR)
system (open circuit or
short to earth or power
supply)
C1215Wheel speed sensor (RL)
system (open circuit or
short to earth or power
supply)
C1201Wheel speed sensor (FR)
system (sensor output
error)ProhibitedEnabled
(Prohibited
when three
or more
wheels
have fault.)ProhibitedProhibitedProhibitedProhibited
C1206Wheel speed sensor (FL)
system (sensor output
error)
C1211Wheel speed sensor (RR)
system (sensor output
error)
C1216Wheel speed sensor (RL)
system (sensor output
error)
C1222Wheel sensor system
(abnormal power supply
voltage)ProhibitedEnabled
(Prohibited
when three
or more
wheels
have fault.)ProhibitedProhibitedProhibitedProhibited
C1225Wheel speed sensor
system (sensor output
error)ProhibitedProhibitedProhibitedProhibitedProhibitedProhibited

CONSTRUCTION DIAGRAM
ACTIVE STABILITY CONTROL SYSTEM (ASC)35C-10
C1226Control solenoid valve
(FR) pressure holding
systemProhibitedProhibitedProhibitedProhibitedProhibitedProhibited
C1231Control solenoid valve
(FR) decompressing
system
C1236Control solenoid valve
(FL) pressure holding
system
C1241Control solenoid valve
(FL) pressure reducing
system
C1246Control solenoid valve
(RR) pressure holding
system
C1251Control solenoid valve
(RR) pressure reducing
system
C1256Control solenoid valve
(RL) pressure holding
system
C1261Control solenoid valve
(RL) decompressing
system
C1266Motor system (seizure)ProhibitedBack-up
controlProhibitedProhibitedProhibitedProhibited
C1273Motor relay stuck OFF
C1274Motor relay stuck ON
C1276Valve relay systemEnabledEnabledEnabledEnabledProhibitedProhibited
C1278Valve relay system stuck
offEnabledEnabledEnabledEnabledProhibitedProhibited
C1279Valve relay system stuck
onProhibitedEnabledProhibitedProhibitedProhibitedProhibited
C1300Cut valve (FR/RL)
<primary> systemProhibitedProhibitedProhibitedProhibitedProhibitedProhibited
C1305Suction valve (FR/RL)
<primary> system
C1310Cut valve (FL/RR)
<secondary> system
C1315Suction valve (FL/RR)
<secondary> system
C1340Stop lamp switch signal
errorEnabledEnabledProhibitedProhibitedProhibitedProhibited
C1345Low brake fluid levelEnabledEnabledEnabledEnabledEnabledEnabled
C1364Internal malfunction of
pressure sensorProhibitedEnabledProhibitedProhibitedProhibitedProhibited
C1366Lateral G-sensor signal
errorEnabledEnabledProhibitedProhibitedProhibitedProhibited
Diagnosis
code No.Item ABS EBD TCL ASC
Engine
controlBrake
controlEngine
controlBrake
control