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15-370000-00
HFM (intake air
temperature)Cooling fan module
DSI 6 A/T (ATF
temperature)Coolant
temperature senso
r
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
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15-390000-00
D. Cooling fan and A/C compressor control
Conditions for cooling fan ▶
The cooling fan module controls the cooling fan relay, high speed relay and low speed relay. The
cooling fan is controlled by the series and parallel circuits.
A/C switch Cooling fanCoolant temperature Refrigerant pressure
A/C compressor
OFF OFF Coolant temp. < 90℃ -
LO 90℃ ≤ Coolant temp.
< 105℃-
HI 105℃ ≤ Coolant temp. -
ONLO
Coolant temp. < 105℃Refrigerant pressure <
18 bar
ON
HI 18 bar ≤ Refrigerant
pressure
HI 105℃ ≤ Coolant tem
p.
< 115℃-
HI115℃ ≤ Coolant temp. -
OFF (cut)
A/C compressor OFF conditions ▶
Coolant temperature: below -20℃ or over
115℃
Approx. 4 seconds after starting the engine
Engine rpm: below 650 rpm or over 4500 rpm
When abrupt acceleration
Refrigerant pressure:
* OFF below 2.0 kg/㎠, then ON over 2.4 kg/㎠
* OFF over 30 kg/㎠, then ON below 21.4 kg/㎠ -
-
-
-
-
The output voltage from refrigerant pressure sensor is 1.7 V to 3.5 V when the refrigerant pressure
is 10 to 24 kgf/㎠ with A/C "ON".Output voltage according to refrigerant pressure ▶
Cooling fan controls according to ATF ▶
ATF temperature Fan condition Remark
Over 110˚CHigh speed -
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15-40
Relay box in engine compartment
(13) High speed
A. Overview
The supplementary electrical heater is installed in DI engine equipped vehicle as a basic
equipment. The PTC system is operated according to two temperature values measured at the
coolant temperature sensor and HFM sensor. This device is mounted in the heater air outlet and
increase the temperature of air to the passenger compartment. Because PTC system is heated by
electrical power, high capacity alternator is required. PTC does not operate during engine
cranking, while the battery voltage is lower than 11 V or during preheating process of glow plugs.
B. Components
HFM (intake air
temperature)
Coolant temperature
sensorPTC heater
PTC 2 relay (PTC
heater 2, 3)
PTC heater
3 (40A)
PTC heater
2 (40A)
PTC heater
1 (40A)
D20DTR ECU
PTC 1 relay
(PTC heater 1)
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15-42
D. Control conditions
Operation Operating condition PTC Heater
HI
(PTC2)- Coolant temperature < 15℃PTC HI ON
LO
(PTC1)- Coolant temperature 15℃ ≤ 65℃, intake air
temperature ≤ -10℃
- Coolant temperature 15℃ < 65 to 60℃, intake air
temperature <-10℃ to 0℃
- Coolant temperature 15℃ ≤ 60℃, intake air
temperature ≤ 0℃ to 5℃PTC LO ON
Stop- A/C blower switch OFF
- Defective ambient air temperature sensor
(including open or short circuit)
- Engine cranking
- Low battery voltage (below 11V)
- During pre-glow process (glow indicator ON)
Operation diagram for PTC heater LO (step 2) ▶
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15-450000-00
(15) CDPF control
A. Overview
As the solution for environmental regulations and PM Particle Material) of diesel engine, the low
emission vehicle is getting popular. This vehicle is equipped with an extra filter to collect the soot
and burn it again so that the amount of PM in the exhaust gas passed through the DOC (Diesel
Oxidation Catalyst) is reduced. The CDPF (Catalyst & Diesel Particulate Filter) is an integrated filter
including DOC (Diesel Oxidation Catalyst) and DPF (Diesel Particulate Filter).
For details, refer to Chapter "CDPF".
B. Components
Oxygen
sensorFront
EGT sensorCDPF
(DOC + DPF)Rear
EGT sensor
Differential pressure
sensorD20DTR ECUElectric throttle body
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15-470000-00
Diff. pres. sensor: Measure
pressure between front sid
e
and rear side of CDPF
ECU (DCM 3.7)
Injector: Control post
injection
D. Operation process
When the differential pressure sensor detects the pressure difference between the front and the
rear side of CDPF, the sensor sends signal indicating the soot is accumulated and the post
injection is performed to raise the temperature of exhaust gas. The amount of fuel injected is
determined according to the temperature of exhaust gas detected by the rear temperature sensor.
If the temperature is below 600°C, the amount of fuel injected is increased to raise the
<009b008c00940097008c00990088009b009c0099008c005500470070008d0047009b008f008c0047009b008c00940097008c00990088009b009c0099008c00470090009a00470096009d008c00990047005d0057005700b6006a00530047009b008f008c00
47008800940096009c0095009b00470096008d0047008d009c>el injected is decreased or not
controlled. When the engine is running in low load range, the amount of post injection and the
amount of intake air are controlled. It is to raise the temperature by increasing the amount of fuel
while decreasing the amount of intake air.
Front EGT sensor: Measure
DOC temp.
Rear EGT sensor: Measure
DPF temp.
Electronic throttle body
Control intake air mass
T-MAP sensor
Intake air
mass
Exceed PM
limitBooster
pressure/
temperaturePost injection
Control intake
air mass
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01-8
Front View ▶
NO. FUNCTION NO. FUNCTION
1 HFM Sensor 12 Intake Manifold
2 Intake Air Duct 13 Cylinder Head
3 Cylinder Head Cover 14 Exhaust Manifold
4 Ignition Coi 15 Dipstick Guide Tube and Gauge
5 Spark Plug Connector 16 Connecting Rod
6 Fuel Distributor 17 Crankshaft
7 Injector 18 Engine Mounting Bracket
8 Exhaust Camshaft 19 Starter
9 Intake Camshaft 20 Crankcase
10 Valve Tappet 21 Oil Pump Sprocket
11 Intake Valve 22 Oil Pan
NO. FUNCTION NO. FUNCTION
23 Camshaft Adjuster 29 Oil Pump Drive Chain
24 Oil Filler Cap 30 Oil Strainer
25 Engine Hanger Bracket 31 Oil Pump
26 Cooling Fan and Viscous Clutch 32 Ring Gear and Flywheel of Drive Plate
27 Oil Filter 33 Piston
28 Timing Chain
Side View ▶
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04-8
The cooling fans are mounted behind the radiator in the engine compartment. The electric cooling
fans increase the flow of air across the radiator fins and across the condenser on air conditioned
(A/C)-equipped vehicles.
This helps to speed cooling when the vehicle is at idle or moving at low speeds.
All models have two fans. The main fan is 320 mm (12. 6 inches) in diameter with seven blades to
aid the airflow through the radiator and the condenser. An electric motor attached to the radiator
support drives the fan.
The auxiliary fan is 320 mm (12.6 inches) in diameter.
A/C Off or Non-AC Model ▶
The cooling fans are actuated by the engine control module (ECM) using a low-speed
cooling fan relay, a high-speed cooling fan relay and a cooling fan motor relay.
The ECM will turn the cooling fans on at low speed when the coolant temperature reaches
95°C(203°F) and at high speed when the coolant temperature reaches 105°C(221°F).
The ECM will change the cooling fans from high peed to low speed at 100°C(212°F) and
will turn the cooling fans off at 90°C (194°F). -
-
-
A/C On ▶
The ECM will turn the cooling fans on at low speed when the A/C system is on. The ECM
will change to high speed when the high side A/C pressure reaches 1860 kPa (269.8 psi).
The cooling fans will return to low speed when the high side A/C pressure reaches 1378
kPa (199.8 psi). -
-
7) Engine Coolant Temperature Sensor
The Engine Coolant Temperature (ECT) sensor uses a temperature to control the signal voltage to
the Engine Control Module (ECM).
8) Coolant Temperature Gauge
The coolant temperature gauge controls the instrument panel temperature indicator. The coolant
temperature gauge is located with ECT sensor.