Page 225 of 751

15-250000-00
(8) Swirl control
A. Overview
Variable swirl valve ▶
The strong swirl caused by intake air is important element for anti-locking function in diesel engine. The
swirl control valve partially closes the intake port to generate the swirl according to the engine conditions.
When the engine load is in low or medium range, the swirl could not be generated because the air flow is
slow. To generate strong swirl, there are two passages in intake manifold, and one of them has the valve
to open and close the passage. When the valve closes the passage, the air flow through the another
passage will be faster, and the strong swirl will be generated by the internal structure of the passage. This
swirl makes the better mixture of air and fuel, eventually the combustion efficiency in combustion
chamber could be improved. This provides the enhanced fuel consumption, power and EGR ratio.
Components ▶
HFMCrankshaft position sensorVariable swirl valve
Coolant temperature
sensorAccekerator pedal
moduleD20DTR ECU
Page 239 of 751

15-390000-00
HFM (intake air
temperature)Cooling fan
module
DSI 6 A/T (ATF
temperature)Coolant
temperature
sensor
Refrigerant
pressure sensor
Relay box
(12) Cooling fan control
A. Overview of cooling fan and A/C compressor
The cooling system maintains the engine temperature at an efficient level during all engine operating
conditions. The water pump draws the coolant from the radiator. The coolant then circulates through
water jackets in the engine block, the intake manifold, and the cylinder head. When the coolant reaches
the operating temperature of the thermostat, the thermostat opens. The coolant then goes back to the
radiator where it cools. The heat from automatic transmission is also cooled down through the radiator
by circulating the oil through the oil pump. ECU controls the electric cooling fans with three cooling fan
relays to improve the engine torque and air conditioning performance.
For detailed information, refer to Chapter "Air Conditioning System".
B. Components
A/C compressor
D20DTR ECU
Page 250 of 751

15-50
E. Cautions
Use only specified Engine Oil (approved by MB Sheet 229.51) for CDPF. -
Use only specified engine oil (Low Ash Oil) ▶
The vehicle equipped with CDPF should use specific engine oil to improve the engine performance
and fuel economy, and ensure the service life of CDPF. -
Issue with normal engine oil ▶
Sulfur, one of the contents of engine oil is burned and generates soot that is not regenerated by the
DPF. This remains on the filter as ashes and keeps accumulating. Eventually, this ashes will block
the filter. -
Benefit for specified engine oil ▶
Minimized the sulfur content of engine oil which reduces the service life.
Improved fuel economy and emission level of CO2 with high performance and low viscosity.
Increased service life of engine oil with high resistance to temperature. -
-
-
Problems when using unspecified engine oil ▶
The service life of filter may be reduced by 30% or more by the ashes accumulated on the filter.
The fuel economy may be reduced because of engine rolling resistance, frequent regeneration of
DPF. -
-
These problems are also caused by oil with high sulfur content, such as tax exemption oil and
heating oil, etc. *
Page 253 of 751
01-4
2) On-engine Service
Disconnect the negative battery cable before removing or installing any electrical unit, or when a
tool or equipment could easily come in contact with exposed electrical terminals.
Disconnecting this cable will help prevent personal injury and damage to the vehicle. The ignition
must also be in LOCK unless otherwise noted. -
Any time the air cleaner is removed, the intake opening should be covered. This will protect
against accidental entrance of foreign material, which could follow the intake passage into the
cylinder and cause extensive damage when the engine is started. -
Page 286 of 751

06-6
2. DESCRIPTION AND OPERATION
1) General Description
The cooling system maintains the engine temperature at an efficient level during all engine operating
conditions.
When the engine is cold, the cooling system cools the engine slowly or not at all. This slow cooling o
f
the engine allows the engine to warm up quickly.
The cooling system includes a radiator and recovery subsystem, cooling fans, a thermostat and
housing, a water pump, and a water pump drive belt. The timing belt drives the water pump.
All components must function properly for the cooling system to operation. The water pump draws the
coolant from the radiator. The coolant then circulates through water jackets in the engine block, the
intake manifold, and the cylinder head. When the coolant reaches the operating
temperature of the thermostat, the thermostat opens. The coolant then goes back to the radiator where
it cools.
This system directs some coolant through the hoses to the heat core. This provides for heating and
defrosting.
The coolant reservoir is connected to the radiator to recover the coolant displaced by expansion from
the high temperatures. The coolant reservoir maintains the correct coolant level.
The cooling system for this vehicle has no radiator cap or filler neck. The coolant is added to the cooling
system through the coolant reservoir.
2) Radiator
This vehicle has a lightweight tube-and-fin aluminum radiator. Plastic tanks are mounted on the upper
and the lower sides of the radiator core.
On vehicles equipped with automatic transaxles, the transaxle fluid cooler lines run through the radiato
r
tank.
A radiator drain plug is on this radiator.
To drain the cooling system, open the drain plug.
3) Coolant Reservoir
The coolant reservoir is a transparent plastic reservoir, similar to the windshield washer reservoir.
The coolant reservoir is connected to the radiator by a hose and to the engine cooling system by anothe
r
hose.
As the vehicle is driven, the engine coolant heats and expands. The portion of the engine coolant
displaced by this expansion flows from the radiator and the engine into the coolant reservoir. The ai
r
trapped in the radiator and the engine is degassed into the coolant reservoir.
When the engine stops, the engine coolant cools and contracts. The displaced engine coolant is then
drawn back into the radiator and the engine. This keeps the radiator filled with the coolant to the desired
level at all times and increases the cooling efficiency.
Maintain the coolant level between the MIN and MAX marks on the coolant reservoir when the system is
cold.
Page 290 of 751

06-10
3) PWM Electric Fan
(1) Advantages and Disadvantages of the PWM Electric Fan
Advantages ▶
Enhanced A/C performance: at low speed, at
idling, driving in city
Reduction of vibration/noise: fan activated by
PWM only when necessary
Reduction of engine consuming power
(V/Fan driving force) by 4 Hp - Cost saving -
-
-
Disadvantage ▶
Poor engine cooling perfomance at low and
high rpm -
4) PWM (Pulse Width Modulation) Unit
It controls the time of the output voltage to control
the fan motor speed independently.
Internal functions ▶
Motor power shutting-off function when
overcurrent is applied
Adverse voltage prevention function
Detection function for the motor lock
Temperature detecting function: The electric
fan operates at FULL speed to cool down
the PWM unit when the interior temperature
of PWM unit is over 120~150°C.
Communication function when failing: The
fail signal is transmitted to the ECU when the
PWM unit is malfunctioning.
Soft start function: The motor speed is
gradually increased when the motor is
initially operated. -
-
-
-
-
-
Page 304 of 751
01-58410-02
ICM
Interior Fuse & Relay
Box (RH)
2. MOUNTING LOCATION
In engine compartment ▶
In vehicle ▶
Fuse & Relay Box In Engine
Compartment
1. OVERVIEW
The ICM (Integrated Control Module) mounted to the back of the STICS is integrated with the door
lock/unlock relay, windshield de-icer relay and turn signal lamp relay. There are four fuse & relay units.
Interior Fuse & Relay
Box (LH)Mounting Location of
ICM
Page 308 of 751
01-98410-02
5. OPERATING PROCESS OF ICM BOX
The following relays are integrated into the ICM (Integrated Control Module) box.
Door lock/unlock relay
Windshield de-icer relay
Turn signal lamp relay -
-
-
1) Overview
2) Mounting Location
Door lock/
unlock relay
Turn signal lamp relay
Windshield
de-icer relay
Inner view of ICM PCB
PAS buzzer
Chime
ICM box
STICS
The relays in the ICM box cannot be replaced respectively; so if the any of the components on
the PCB are defective, they should be replaced as an assembly.