Page 7 of 364

CONSTRUCTION DESCRIPTION
ANTI-SKID BRAKE SYSTEM (ABS)35B-7
EBD FLUID PRESSURE CONTROL
AC208548AB
Ideal distribution curve when 
seated by fixed personsEBD operating conceptual design
Rear braking force
Ideal distribution curve when seated by one persons Braking force distribution curve 
by the existing proportioning valveBraking force distribution 
by EBD control
Front braking force
Braking Force 
Improved
EBD control is 
activate d within the lower slip  ratio 
area where
 ABS is disab l ed.  ABS-ECU calculates 
vehicle
 decelera t ion a nd slip  amou nt of th e four 
whe
e ls based on  the wheel  sp eed senso r  signal.  If 
the rear
 wh eel speed  dif f ers f r om th e ve hicle speed 
by a 
cert ain  level or  more,  ABS-ECU boost, holds,  
and de
pressurises  the rea r  wh eel contro l so leno id 
valve in the h
y drau lic unit, and  then a d just s rear 
whe
e l b r ake  fluid pressure  fa ir ly close to  an ideal dis
-
tribution curve.
INITIAL CHECK
ABS-ECU inter nally activates the self-d iagno stic 
function. ABS-ECU illuminates
 ABS  warning l a mp  for 
3 seconds (in
c lu ding  the in itia l check) 
* after th e ign i-
tion switch is turned  ON. If a n y malf unction is 
detected, ABS-ECU cont
inues illuminating ABS 
war
n ing  lamp and disables ABS cont rol.
NOTE: *: ABS warning lamp may st ay ON af ter the 
ignition 
switch is turned  ON un til t he st artu p ve hicle 
spee
d reaches  approximately 10km/h .  As far  as 
ABS-ECU memorizes  any d i agn osis code related t o  
the 
whee l  speed sen s or malfunct i on record ed  d u ring 
previous ignition ON st atus, ABS-ECU continues illu
-
mina ting  ABS warn ing lamp  until it verif i es that th e 
malfunct
i on  for tha t  co de is resolved (S t a rtup  che ck).  
STARTUP CHECK
When th e st artup  veh i cle sp eed re ache s app roxi-
mately 10 km/h, ABS-ECU performs the following 
checks.
•Motor,  solen o id valve check (onl y i n  ini t ial  st ar-
tup*)
Operat es  the motor relay in ECU  and checks  the 
pump motor op eratio n. At the  same time, 
ABS-ECU sequentially e nergizes each solenoid 
valve in a ve ry sh ort perio d and ch ecks the   valve 
ope ration .
NOTE: *: Initia l st artu p ind i ca tes a  first st artup  af ter 
the
 system has st arted .
•Whee l speed  sensor check
ABS-ECU che cks for a n y whee ls  that ha ve no t 
received whee l sp eed sens or signal from  the 
st artu p.
CONSTANT CHECK
ABS-ECU con s t antly ch ecks th e following  item.
•ABS-ECU
Performs se lf-diagnosis in ECU.
•ECU power supply
Checks if  ECU po we r sup p ly volt ag e reaches within  
the  operat ional range .
•Whee l speed  sensor
•Monitors the ou tput volt age  of the sensor sig-
nal wiring ha rness an d che c ks for a bnormal 
output
 volt ag e (ope n/sho r t circuit).
•Checks fo r any wheels tha t  do n o t send pu lse  
sig
nal while th e ve hicle is in  motion.
•Checks if wheel  spee d which is abno rmally 
high
er or lo we r than  the vehicle speed  is 
inpu
t.
•Pump mo tor and  solenoid  valve
Checks tha t  ABS-ECU outp u t signal and t he ope rat-
ing co ndition of  the pump motor an d so leno id 
valve agree
 with ea ch ot her . 
         
        
        
     
        
        Page 9 of 364

CONSTRUCTION DESCRIPTION
ANTI-SKID BRAKE SYSTEM (ABS)35B-9
C1226Control solenoid 
valve (FR) pressure 
holding system ProhibitedProhibitedOutput 
permittedONON
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 
(stuck)ProhibitedEnabledOutput 
permittedOFFON
C1273Motor relay stuck 
off
C1274Motor relay stuck 
on
C1276Valve relay systemSystem 
shut-downSystem 
shut-downOutput 
permittedONON
C1278Valve relay system 
stuck offSystem 
shut-downSystem 
shut-downOutput 
permittedONON
C1279Valve relay system 
stuck onProhibitedEnabledOutput 
permittedOFFON
Diagnosis 
code No.Item Action during fail-safe operation
ABS control EBD control CAN output Brake 
warning 
lampABS 
warning 
lamp 
         
        
        
     
        
        Page 95 of 364
GROUP 13A
MULTIPOINT FUEL INJECTION (MPI) 
<4A9>
CONTENTS
GENERAL INFORMATIO N  . . . . . . . .13A-2
FUEL INJECTION CONTROL . . . . . .13A-9
THROTTLE VALVE OPENING  
ANGLE CONTROL AND IDLE  
SPEED CONTROL . . . . . . . . . . . . . . .13A-10
IGNITION TIMING AND  
DISTRIBUTION CONTROL . . . . . . . .13A-11
OTHER CONTROL FUNCTIONS . . . .13A-11
FAN RELAY CONTROL . . . . . . . . . . .13A-12
CONTROLLER AREA NETWORK  
(CAN)  . . . . . . . . . . . . . . . . . . . . . . . . .13A-13
DIAGNOSIS SYSTEM. . .  . . . . . . . . . .13A-14 
         
        
        
     
        
        Page 96 of 364
GENERAL INFORMATION
MULTIPOINT FUEL INJECTION (MPI) <4A9>13A-2
GENERAL INFORMATION
M2132000100990
Although the control systems are basically the same 
as those of the 4G1-Non-Turbo engine used in the 
COLT, the following improvements have been added.
ImprovementRemark
Dual oxygen sensor is used Higher reliability of air-fuel ratio control
Fan relay control is changedAbolish the two stage control of the fan rotating speed. 
         
        
        
     
        
        Page 97 of 364

GENERAL INFORMATION
MULTIPOINT FUEL INJECTION (MPI) <4A9>13A-3
SYSTEM BLOCK DIAGRAM
AK600486
Barometric pressure sensorThrottle valve control servo
Manifold absolute pressure
sensor
Engine coolant
temperature sensor
No.1 injector
No.2 injector
No.3 injector
No.4 injector
No.1 Ignition coil
No.2 Ignition coil
No.3 Ignition coil
No.4 Ignition coil
Engine control relay
Throttle valve control servo relay
A/C compressor relay
Fuel pump relay
Alternator G terminal
Cooling fan control relay
Purge control solenoid valve
Diagnostic output terminal
Intake air temperature sensor
Accelerator pedal
position sensor (main) Throttle position sensor (sub)
Camshaft position sensor
Crank angle sensor
Oxygen sensor (front)
Oxygen sensor (rear)
Alternator FR terminal
Inhibitor switch 
Detonation sensor
Ignition switch-IG
Ignition switch-ST
Stop lamp switch
Power supply
Accelerator pedel
position sensor (sub) Throttle position sensor (main) 
Throttle valve control unitEngine control unit
Engine-ECU  or 
Engine-CVT-ECU 
Throttle opening feedback control Oxygen sensor heater (front)
Oxygen sensor heater (rear)
[1] Fuel injection control
[2] Throttle valve opening control
     and idle speed control
[3] MIVEC (Mitsubishi Innovative
     Valve timing Electronic
     control system)
[4] Ignition timing control
[5] Engine control relay control
[6] Throttle valve control servo
     relay control
[7] Fuel pump relay control
[8] Oxygen sensor heater
     control
[9] Fan relay control
[10] A/C compressor relay
       control
[11] Alternator control
[12] Purge control
[13] EGR control 
[14] Diagnostic output
[15] RAM data transmission
Oil feeder control valve 
(for MIVEC)
EGR valve 
(Stepper motor) 
AB 
         
        
        
     
        
        Page 98 of 364

GENERAL INFORMATION
MULTIPOINT FUEL INJECTION (MPI) <4A9>13A-4
CONTROL SYSTEM DIAGRAM
AK600525
1  Oxygen sensor
    (front)4  Intake air temperature
    sensor
3  Manifold absolute
    presssure sensor
2  Oxygen sensor (rear) 3  Throttle valve control
    servo
10 Throttle position sensor 
(main)
2  Purge control
    solenoid valve
8  Engine coolant
    temperature sensor
9  Detonation sensor
7  Crank angle sensor
6  Camshaft position sensor
4 Oil feeder control valve
1  Injector
AB
M
1   Oxygen sensor (front)
2   Oxygen sensor (rear)
3   Manifold absolute
     presssure sensor
4   Intake air temperature
     sensor
5   Throttle position
     sensor 
(sub)
6   Camshaft position
     sensor
7   Crank angle sensor
8   Engine coolant
     temperature sensor
9   Detonation sensor
10 Throttle position
     sensor  (main) 1  Injector
2  Purge control
    solenoid valve
3  Throttle valve control
    servo
4  Oil feeder control
    valve
Power supply
Ignition switch-IG
Ignition switch-ST
Accelerator pedal
position sensor
(main)
Accelerator pedal
position sensor
(sub)
Alternator FR
terminal
Stop lamp switchEngine-ECUEngine control relay
Fuel pump relay 
A/C compressor relay
Throttle valve
control servo relay
Ignition coil
Cooling fan 
control relay
Diagnosis output
Alternator G terminal
Oxygen sensor heater
(front)
Oxygen sensor heater
(rear)
Canister Air
inlet
Catalytic converter From fuel
pump
5   Throttle position sensor 
(sub)
Barometric
pressure
sensor 
         
        
        
     
        
        Page 99 of 364

GENERAL INFORMATION
MULTIPOINT FUEL INJECTION (MPI) <4A9>13A-5
AK403079
1  Oxygen sensor
    (front)4  Intake air temperature
    sensor
3  Manifold absolute
    presssure sensor
2  Oxygen sensor (rear) 4  Throttle valve control
    servo
10 Throttle position sensor 
(main)
2  EGR valve
    (stepper motor) 3  Purge control
    solenoid valve
8  Engine coolant
    temperature sensor
9  Detonation sensor
7  Crank angle sensor
6  Camshaft position sensor
5 Oil feeder control valve
1  Injector
AC
1   Oxygen sensor (front)
2   Oxygen sensor (rear)
3   Manifold absolute
     presssure sensor
4   Intake air temperature
     sensor
5   Throttle position
     sensor (sub)
6   Camshaft position
     sensor
7   Crank angle sensor
8   Engine coolant
     temperature sensor
9   Detonation sensor
10 Throttle position
     sensor  (main) 1  Injector
2  EGR valve
    (stepper motor)
3  Purge control
    solenoid valve
4  Throttle valve control
    servo
5  Oil feeder control
    valve
Power supply
Ignition switch-IG
Ignition switch-ST
Accelerator pedal
position sensor
(main)
Accelerator pedal
position sensor
(sub)
Inhibitor switch
Alternator FR
terminal
Stop lamp switchEngine-
CVT-ECUEngine control relay
Fuel pump relay 
A/C compressor relay
Throttle valve
control servo relay
Ignition coil
Cooling fan 
control relay
Diagnosis output
Alternator G terminal
Oxygen sensor heater
(front)
Oxygen sensor heater
(rear)
Canister Air
inlet
Catalytic converter From fuel
pump
5   Throttle position sensor 
(sub)
Barometric
pressure
sensor 
         
        
        
     
        
        Page 101 of 364

GENERAL INFORMATION
MULTIPOINT FUEL INJECTION (MPI) <4A9>13A-7
Throttle position sensor This sensor detects the position of the throttle valve 
and inputs it into the engine-ECU  or 
engine-CVT-ECU . Based on the voltage that 
is output by this sensor, the engine-ECU  or 
engine-CVT-ECU  effects throttle valve 
feedback control.
Accelerator pedal position sensor This sensor detects the position of the accelerator 
and inputs it into the engine-ECU  or 
engine-CVT-ECU . Based on the voltage that 
is output by this sensor, which determines the 
accelerator position (and the intention of the driver), 
the engine-ECU  or engine-CVT-ECU  
effects appropriate fuel injection and throttle valve 
position controls.
Camshaft position sensorThis sensor detects the top-dead-center (TDC) of the 
compression stroke of each cylinder.
Crank angle sensorThis sensor detects the crank angle and inputs it into 
the engine-ECU  or engine-CVT-ECU . 
The engine-ECU  or engine-CVT-ECU  
effects injector control and other controls in 
accordance with the signals received from this 
sensor.
Detonation sensorThis sensor, which contains a piezoelectric element, 
detects the vibration of the cylinder block that results 
from knocking. The engine-ECU  or 
engine-CVT-ECU  detects only the knocking 
of the engine from these vibrations, in order to retard 
the ignition timing in accordance with the strength of 
the knocks.
Alternator FR terminalThis terminal is used for detecting the duty cycle ratio 
that energizes the alternator field coil.
Inhibitor switch This is a contact point type switch that inputs a signal 
into the engine-CVT-ECU to determine whether the 
shift lever is in the neutral position.
Stop lamp switchThis is a contact point type switch that detects how 
the brake pedal is depressed.
Actuators
Engine control relayThis relay turns ON and OFF the engine-ECU  
or engine-CVT-ECU  power circuit.
Throttle valve control servo relayThis relay turns ON and OFF the actuation power 
circuit for the throttle valve control servo in the 
engine-ECU  or engine-CVT-ECU .
InjectorThe injectors inject fuel in accordance with the 
injection signals received from the engine-ECU 
 or engine-CVT-ECU .
Ignition coil (with power transistor)Applies ignition coil primary current intermittently in 
accordance with the ignition signals received from 
the engine-ECU  or engine-CVT-ECU , 
in order to generate high voltage for ignition.
Name Function