Page 254 of 1336

The engine ECU calculates the accelerator pedal based on the input signals from various sensors, and
controls the overall operation of the vehicle.
The ECU receives the signals from various sensor through data line, and performs effective air-fuel ratio
control based on these signals.
The crankshaft speed (position) sensor measures the engine speed, and the camshaft speed (position)
sensor determines the order of injections, and the ECU detects the amount of the accelerator pedal
depressed (driver's will) by receiving the electrical signals from the accelerator pedal sensor.
The mass air flow sensor detects the volume of intake air and sends the value to the ECU.
The major function of the ECU is controlling air-fuel ratio to reduce the emission level (EGR valve control)
by detecting instantaneous air flow change with the signals from the mass air flow sensor.
Also, the ECU uses the signals from the coolant temperature & air temperature sensors, booster pressure
sensor, atmospheric pressure sensor to: a) determine injection starting point and set value for pilot
injection, and b) deal with various operations and variable conditions.
Page 260 of 1336
1719-02 Swirl control valve
Operates variably in accordance with the engine
load and rpm.
* For more information, refer to Chapter "Engine
Control".
1719-01 Intake manifold
Passage for intake air during the operation of
variable swirl valve
1719-16 Electric throttle body
* For more information, refer to Chapter "Engine
Control".
1. OVERVIEW
The intake system for D20DTF engine is equipped with an electric throttle body which includes a flap.
This flap is controlled by an electrical signal to cut off the intake air entering to the engine when the
ignition switch is turned off. To be sure to get the optimized swirl in intake manifold, the swirl valve and
dual type port have been adopted. And, the improved HFM sensor has been adopted to control the
intake air volume more precisely.
2. COMPONENTS
2330-01 Intercooler assembly
Page 261 of 1336
0000-00
2313-15 HFM (Hot Film Air-Mass) sensor
HFM sensor, version 6
* For more information, refer to Chapter "Engine
Control".
2313-01 Air cleaner assembly and
resonator
Page 273 of 1336

0000-00
2) Inspection of Turbocharger
On-board Inspection 1.
Check the bolts and nuts foe looseness or missing
Check the intake and exhaust manifold for looseness or damage
Check the oil supply pipe and drain pipe for damages
Check the housing for crack and deterioration -
-
-
-
Inspection of turbine 2.
Remove the exhaust pipe at the opening of the turbine and check, with a lamp, the existence of
interference of housing and wheel, oil leakage and contamination (at blade edge) of foreign
materials.
Interference: In case where the oil leak sign exists, even the small traces of interferences on the
turbine wheel mean, most of times, that abrasion has occurred on the journal bearing. Must
inspect after overhauling the turbocharger.
Oil Leakage: Followings are the reasons for oil leakage condition -
-
Problems in engine: In case where the oil is smeared on inner wall section of the exhaust gas
opening.
Problems in turbocharger: In case where the oil is smeared on only at the exhaust gas
outlet section. *
* When problem occurs with the turbocharger, it could cause engine power decline,
excessive discharge of exhaust gas, outbreak of abnormal noise and excessive
consumption of oil.
Idling for long period of time can cause oil leakage to the turbine side due to low pressure of
exhaust gas and the rotation speed of turbine wheel. Please note this is not a turbocharger
problem.
Oil Drain Pipe Defect
In case where oil flow from the turbocharger sensor housing to the crank case is not smooth would
become the reason for leakage as oil builds up within the center housing. Also, oil thickens (sludge)
at high temperature and becomes the indirect reason of wheel hub section. In such case, clogging
and damage of the oil drain pipe and the pressure of blow-by gas within the crank case must be
inspected.
Damages due to Foreign Materials
When the foreign materials get into the system, it could induce inner damage as rotating balance of
the turbocharger gets out of alignment. -
-
Page 287 of 1336
0000-00
E-VGT turbocharger
Improves engine power
T-MAP sensor
Boost pressure and
temperature
2. COMPONENTS
Engine ECU (D20DTF)
E-VGT duty controlAccelerator pedal position
sensor
Transfers accelerating demand
to ECU
Atmospheric pressure, RPM
signal
HFM sensor
Improves the engine powerCoolant temperature sensor
Operates the VGT according to
engine warm-up
For more information about control logic, refer to Chapter "Engine Control".
Page 299 of 1336

2. INSPECTION
Possible Cause Action
Coolant level
is too low- Leak from the radiator
- Leak from the auxiliary reservoir
- Leak from the heater core- Replace the radiator
- Replace the auxiliary reservoir
- Replace the heater
- Leak from the coolant hose connections
- Damaged coolant hose- Reconnect the hose or replace
the clamp
- Replace the hose
- Leak from the water pump gasket
- Leak from the water pump internal seal- Replace the gasket
- Replace the water pump
- Leak from the water inlet cap
- Leak from the thermostat housing- Replace the water inlet cap
gasket
- Replace the thermostat sealing
- Incorrect tightening torque of the
cylinder head bolts
- Damaged cylinder head gasket- Tighten the bolts to the specified
torque
- Replace the cylinder head
gasket
Coolant
temperature is
too high- Coolant leakage (Coolant level is low)
- Improper coolant mixture ratio
- Kinked coolant hose- Add coolant
- Check the coolant concentration
(Anti-freeze)
- Repair or replace the hose
- Defective thermostat
- Defective water pump
- Defective radiator
- Defective auxiliary reservoir or tank cap- Replace the thermostat
- Replace the water pump
- Replace the radiator
- Replace the auxiliary reservoir
or tank cap
- Cracks on the cylinder block or cylinder
head
- Clogged coolant passages in the
cylinder block or cylinder head- Replace cylinder block or
cylinder head
- Clean the coolant passage
- Clogged radiator core - Clean the radiator core
- Improper operation of cooling fan - Replace the cooling fan or repair
the related circuit
- Defective temperature sensor or faulty
wiring- Replace the sensor or repair the
related wiring
Coolant
temperature is
too low- Thermostat is stuck open - Replace the thermostat
- Improper operation of cooling fan - Replace the cooling fan or repair
the related circuit
- Defective temperature sensor or faulty
wiring- Replace the sensor or repair the
related wiring
Page 304 of 1336
0000-00
Electric fan
Circulates the fresh air forcibly to exchange heat
with the radiator core fin.
Coolant temperature sensor
Measures the coolant
temperature and sends the
result to the engine ECU.
Radiator
Releases heat through fins and cools down the hot coolant as the
coolant passes through the tube of the radiator core.
Page 354 of 1336
1793-01
E-EGR bypass valve Solenoid valve Drivien byVacuum
(Solenoid valve)
1. SPECIFICATION
Item
E-EGR valve Motor EGR response time 50 mS
Driven by DC motor
Valve EGR gas flow rate 120 Kg/h
Position sensor Sensing type Hall sensor
Supply voltage
Signal range 5% ~ 95%
Max. current consumption
E-EGR cooler Cooling capacity 8.3 kW or more
Coolin fin type Wavy fin
Coller type U-shaped