A/C-ECU
HEATER, AIR CONDITIONING AND VENTILATION55-8
COMMUNICATION
A/C-ECU performs the signal transmission and
reception with each ECU via CAN (Controller Area
Network)*
1. Also, with the heater control panel, it
transmits and receives signals via serial communica
-
tion.
NOTE: : For details of CAN communication, refer to
GROUP 54C
− Controller Area Network P.54C-2.
CAN COMMUNICATION INPUT SIGNALS TABLE
DIAGNOSTIC FUNCTION
A/C-ECU has the following functions for easier sys-
tem checks.
•DIAGNOSTIC FUNCTION
•Service data output
•Actuator test
NOTE: For each item, refer to the Workshop Manual.
AC506202
ETACS-ECU Heater control panelSRS-ECU
Engine-ECU
Combination meter A/C-ECU
: Interactive communicationCAN communication
SERIAL communication
AC
SignalTransmitter ECU
Engine coolant temperature signalENGINE-ECU
Vehicle speed signal
Engine speed signal
Ambient temperature signalETACS-ECU
Wiper signal
Ignition key signal
Average ambient temperature signalCOMBINATION METER
AUTO-CRUISE CONTROL SYSTEM
ENGINE AND EMISSION CONTROL17-6
SYSTEM FUNCTIONS
.
SET FUNCTION
1. During driving with the vehicle speed range from
approximately 40 to 200 km/h (25 to 125 mph),
press and release the "COAST/SET" switch.
2. The vehicle speed when the "COAST/SET" switch
is released is memorized. Thereafter, the constant
speed driving is performed at that vehicle speed.
3. When the "COAST/SET" switch is operated
during the driving with the vehicle speed of
approximately 200 km/h (125 mph) or more, the
constant speed driving will not be performed.
.
COAST FUNCTION
1. When the "COAST/SET" switch is continuously
pressed for 0.5 seconds or longer during constant
speed driving, the throttle valve becomes fully
closed while the switch is pressed, and the
vehicle is decelerated.
2. When the "COAST/SET" switch is released, the
vehicle speed at that time is now memorized.
Thereafter, the constant speed driving is
performed at that vehicle speed.
3. Also when the "COAST/SET" switch is pressed
for less than 0.5 second, the vehicle is
decelerated 1.6 km/h (1 mph) from the vehicle
speed of constant speed driving, and the
decelerated vehicle speed is now memorized.
Thereafter, the constant speed driving is
performed at that vehicle speed.
4. When the "COAST/SET" switch is continuously
pressed and the vehicle speed is decelerated to
approximately 40 km/h (25 mph) or less, the set
function and coast function are cancelled, and the
constant speed driving is cancelled.
.
RESUME FUNCTION
1. When the "CANCEL" switch is pressed or the
brake pedal is depressed during the constant
speed driving, it cancels the constant speed
driving.
2. Subsequently, when the "ACC/RES" switch is
pressed during driving with the vehicle speed of
approximately 40 km/h (25 mph) or more, the
constant speed driving is performed with the
vehicle speed memorized at the last cancellation
of constant speed driving.
.
ACCEL FUNCTION
1. When the "ACC/RES" switch is continuously
pressed for 0.5 second or more during constant
driving, it accelerates the vehicle with specified
acceleration while the switch is pressed.
2. Then, when the "ACC/RES" switch is released,
the vehicle speed at that time is now memorized.
Thereafter, the constant speed driving is
performed at that vehicle speed.
3. Also, when the "ACC/RES" switch is pressed for
less than 0.5 second, the vehicle is accelerated
1.6 km/h (1 mph) from the vehicle speed of
constant speed driving, and the accelerated
vehicle speed is now memorized. Thereafter, the
constant speed driving is performed at that
vehicle speed.
4. It is possible to keep pressing the "ACC/RES"
switch until the vehicle speed is accelerated to
approximately 200 km/h (125 mph) or above.
However, after the "ACC/RES" switch is released,
the vehicle speed of approximately 200 km/h (125
mph) becomes the newly memorized vehicle
speed. Thereafter, the constant speed driving is
performed at that speed.
.
CANCEL FUNCTION
When any of the following conditions are satisfied,
the constant speed driving will be cancelled.
•The auto-cruise control system is stopped by the
pressing the "ON OFF" switch.
•The "CANCEL" switch is pressed.
•The brake pedal is depressed.
•The clutch pedal is depressed
•The selector lever is shifted to the "N" position
•The vehicle speed becomes approximately 40
km/h (25 mph) or less.
•The vehicle speed is reduced 15 km/h (9 mph) or
more from the speed at which the constant speed
driving was started.
•An abnormality occurs in the vehicle speed sig-
nal.
•The engine coolant temperature becomes abnor-
mally high.
•An abnormality occurs to the ECM.
•An abnormality occurs to the TCM
•An abnormality occurs to the CAN communica-
tion.
.
EMISSION CONTROL
ENGINE AND EMISSION CONTROL17-10
CRANKCASE VENTILATION SYSTEMM2171000400129
A blow-by gas reduction device prevents blow-by
gas from being expelled into the atmosphere and is
of closed type. A positive crankcase ventilation
(PCV) valve is provided in the ventilation hose from
the rocker cover to the intake manifold. During low
load driving, clean air is supplied to the crankcase by
the air intake hose via the breather hose and rocker
cover, and it mixes with the blow-by gas in the crank
-
case. The blow-by gas in the crankcase is induced to
the intake manifold through the rocker cover and
PCV valve. During high load driving, blow-by gas in
the crankcase is induced to the intake manifold
through the rocker cover and PCV valve and at the
same time also via the air intake hose and throttle
body due to negative pressure in the air cleaner.
Emission
reduction
systemsAir-fuel ratio
feedback
controlDecrease of CO, HC and NOx
Controls air-fuel ratio of air-fuel mixture to
become theoretical air-fuel ratio (about 14.7),
which is when the 3-way catalytic converter's
cleaning performance is best. It also controls
optimum fuel supply based on coolant
temperature, driving conditions etc.
•ECM
•Mass airflow sensor
•Injectors
•Heated oxygen sensor
•Crankshaft position sensor
etc.
Catalytic
converterDecrease of CO, HC and NOx
It facilitates oxidation of CO and HC and
reduction of NOx so that all 3 component gases
are cleaned simultaneously.
Monolith catalyst
HC trap
catalytic
converter
During cold operation of engine, exhaust HC is
temporarily absorbed. And then Exhaust HC is
released when temperature reaches to level at
which catalyst is activated. This allows HC to be
reduced.
Monolith catalyst
System Objective / Function Composition parts
AK604142
Air cleaner
PCV valve
AB
Ventilation hose
Breather hose
Flow of blow-by gas and clean air (low load area)
Flow of blow-by gas (high load area)
EMISSION CONTROL
ENGINE AND EMISSION CONTROL17-11
POSITIVE CRANKCASE VENTILATION (PCV)
VA LV E
PCV valve lifts the plunger according to negative pressure in
the intake manifold to create appropriate ventilation for the
crankcase.
EVAPORATIVE EMISSION CONTROL SYSTEMM2171000200147
HC (hydrocarbon) generated in the fuel tank are
adsorbed by the active carbon in the canister and
stored. HC stored in the canister is introduced to the
intake manifold when engine is in operation where it
is mixed with intake air and combusted. ECM intro
-
duces optimum HC amount according to driving con-
ditions and so performs duty control on the
evaporative emission purge solenoid. Also, the evap
-
orative emission purge solenoid is closed during
deceleration or immediately after engine start to
restrict change in air-fuel ratio and prevent engine
from stalling.
AK602324AC
Plunger
From
rocker
coverTo intake
manifold
Spring
AK604143
Evaporative emission
purge solenoid
Mass airflow sensor
ECM Intake air temperature sensor
Manifold absolute pressure
sensor
Engine coolant temperature
sensor
Throttle position sensor
Crankshaft position sensorEvaporative emission
canister
AB
MFI relay
Battery
EMISSION CONTROL
ENGINE AND EMISSION CONTROL17-12
EVAPORATIVE EMISSION PURGE SOLENOID
An evaporative emission purge solenoid is installed in the
intake manifold.The evaporative emission purge solenoid con
-
trols the intake volume of fuel vapor gas from the canister. The
evaporative emission purge solenoid is a duty control type
solenoid valve. When current is not passing through the coil,
nipple A is kept airtight and fuel vapor gas cannot be sucked in.
When current passes through the coil, air can pass between
nipple A and B and fuel vapor gas is sucked in. ECM changes
the ON duty ratio according to engine's operating condition to
control the intake volume of fuel vapor gas.
EXHAUST GAS RECIRCULATION (EGR) SYSTEM
When the combustion gas temperature becomes
high, generation of the environment polluting NOx
(nitrogen oxides) increases rapidly. EGR system is
used to decrease the volume of NOx generated.
EGR system re-circulates exhaust gas inside the
intake manifold. It increases specific heat of the com
-
bustion gases and reduces combustion speed to lower the combustion temperature and reduce the
volume of NOx generated. ECM calculates the EGR
introduction volume according to engine operating
conditions and controls the EGR valve opening angle
at optimum. Also, immediately after the ignition
switch ON signal is input, it drives fully closed step
-
per motor and performs initialization.
AK604745AC
B To canister
To intake manifoldA
AK602245AD
12V
ONOFF
0V100 ms
Evaporative
emission
purge solenoidFrom MFI relay
ECM
AK502987AE
ECMMass airflow sensor
Intake air temperature sensor
Manifold absolute
pressure sensor
Engine coolant
temperature sensor
Throttle position sensor
Crankshaft position sensor BatteryEGR valve
(stepper motor)
EMISSION CONTROL
ENGINE AND EMISSION CONTROL17-15
HEATED OXYGEN SENSOR (3RD)
The heated oxygen sensor (3rd) is installed to the HC trap cat-
alytic converter. The heated oxygen sensor (3rd) detects the
oxygen density of the exhaust gas and outputs the voltage to
the ECM in accordance with the oxygen density.
The ECM uses this output voltage to detect the deterioration of
the HC trap catalytic converter. The structure of the heated oxy
-
gen sensor (3rd) is the same as that of the heated oxygen sen-
sor (rear) installed in the exhaust pipe.
HC TRAP CATALYTIC CONVERTER
DETERIORATION MONITOR
The ECM detects the deterioration of the HC trap catalytic con-
verter.
When reaching the certain operating range, the ECM begins
monitoring the difference in the feedback time between the
heated oxygen sensor (rear) on the upstream of the HC trap
catalyst and the heated oxygen sensor (3rd) on the down
-
stream of the HC trap catalyst. This monitoring allows the ECM
to detect the deterioration of the HC trap catalytic converter.
AK604553
AB
Heated oxygen sensor (3rd)
HC trap catalytic converter
AK604148AB
Heated oxygen sensor (rear) Heated oxygen sensor (3rd)
ECMEngine coolant
temperature sensor
Accelerator pedal
position sensor
Crankshaft position sensor
GENERAL INFORMATION
ENGINE COOLING14-2
GENERAL INFORMATIONM2140000100780
The cooling system is a water-cooled pressurized,
forced circulation type which offers the following fea
-
tures.
•To stabilize engine coolant temperature, the ther-
mostat is located at the coolant inlet port from the
radiator.
•To improve engine cooling performance and save
weight, a plastic tank and aluminum radiator fins
are used.
SPECIFICATIONS
CONSTRUCTION DIAGRAM
ItemSpecification
Cooling methodWater-cooled pressurized, forced
circulation with electrical fan
RadiatorTy p ePressurized corrugate type
Performance kJ/h (kcal/h)222,480 (53,148)
Water pumpTy p eCentrifugal impeller
Drive methodDrive belt
ThermostatTy p eWax pellet with jiggle valve
Valve open temperature °C (°F)82 (180)
AC608448
Condenser fan motor Radiator assemblyRadiator upper hose
assembly
Radiator condenser
tank assembly Radiator fan motor
Cooling fan shroud
Radiator lower hose Transmission oil
cooler line hose
and tube assembly
AB
GENERAL DESCRIPTION
MULTIPORT FUEL SYSTEM (MFI)13A-3
System Block Diagram
AK604116
Mass airflow sensor
Intake air temperature sensor
Intake camshaft position
sensor
Exhaust camshaft position
sensor
Crankshaft position sensor Throttle position sensor (main)
Throttle position sensor (sub)
Accelerator pedal position
sensor (sub) Accelerator pedal position
sensor (main) Engine coolant temperature
sensor Manifold absolute pressure
sensor
Heated oxygen sensor (front)
Heated oxygen sensor (rear)
Power steering pressure
switch Engine oil pressure switch Generator L terminal
Ignition switch-ST
Power supply Ignition switch-IG
CAN communication
(input signal)
· A/C switch
· Vehicle speed
· Fuel level sensor
· Transmission range switch
sensor Heated oxygen sensor
(3rd)*
Knock sensor
Generator FR terminal
Fuel tank temperature sensor
Vehicle speed sensor
[1] Fuel injection control
[2] Ignition timing control
[3] Throttle valve opening angle
control and idle speed control
[4]
MIVEC (Mitsubishi Innovative
Valve timing Electronic Control
system)
[5] Power supply control
(Power supply to sensor,
actuator)
[6] Fuel pump relay control
[7] Starter relay control
[8] Heated oxygen sensor heater
control
[9] A/C compressor relay control
[10] Generator control
[11] Evaporative emission purge
control
[12] EGR control
[13] Diagnosis output
[14] RAM data transmission
CAN communication
(output signal) Intake engine oil control
valve
A/C compressor relay No. 2 injector
No. 3 injector
No. 4 injector
Heated oxygen sensor (front)
heater
Heated oxygen sensor (rear)
heater Throttle actuator control
motor
Throttle actuator control
motor relay No. 1 injector
No. 1 ignition coil
No. 2 ignition coi
No. 3 ignition coi
No. 4 ignition coi
Fuel pump relay
Generator G terminal Heated oxygen sensor (3rd)
heater*
Multiport fuel injection (MFI)
relay Exhaust engine oil control
valve
Evaporative emission ventilation
solenoid Evaporative emission purge
solenoid
EGR valve (stepper motor)*
Starter relay
AB
Sensor, switch Engine control module (ECM) Actuator
NOTE
*1: California