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6) Cooling Fan Control
(1) 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 transaxle is also cooled down through the radiator by
circulating the oil through the oil pump. There are two cooling fans (180W+120W) in G20DF engine. ECU
controls the electric cooling fans with three cooling fan relays to improve the engine torque and air
conditioning performance.
(2) Components
Refrigerant pressure
sensorCoolant temperature
sensorG20DF Engine
ECURelay box in engine
compartment
A/C compressorCooling fan moduleT-MAP sensor
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7) Immobilizer Control
(1) Overview
The Immobilizer System provides an additional theft deterrent to the vehicle in which it is installed and
prevents it from being started by unauthorized persons. The transponder integrated in the key and the
engine control unit have the same code. When the ignition key with the integrated transponder is turned
to the ON position, the ECU (Engine Control Unit) checks the crypto code of the key and, if correct,
allows the vehicle to start the engine.
For details, refer to Chapter "BCM".
(2) Components
Conditions for cooling fan
Immobilizer
antenna
Immobilizer
key
Start motor
Instrument
cluster
BCM
G20DF ECU
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Key approval process
When turning the ignition switch to ON position, the power is supplied to BCM and ECU. ECU
communicate with the immobilizer key to check if it is valid crypto code. If it is valid, ECU start to control
the engine when turning the ignition switch to START position.
The system has 10 seconds of valid time-out period. If the engine does not start in this period, the key
approval process should be done again.
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8) CAN Configuration (P-CAN/B-CAN)
(1) CAN Configuration (P-CAN/B-CAN)
Name Function
ECUElectronic Control Unit
TCUTransmission Control Unit
EPSElectronic Power Steering Unit
BCMBody Control Moudule
SKMSmart Key Moudule
CAN system communicates with the system units in vehicle. It consists of P-CAN and B-CAN according
to the communication speed.
P-CAN & B-CAN: SKM, Instrument cluster, BCM, Disgnostic connector
P-CAN: ECU, ABS & ESP, TCU, E-coupling, EPS unit
Terminal resistance: installed on ECU and BCM
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T-MAP sensor
TurbochargerCDPF
1. MAJOR COMPONENTS (D20DTF(Low CO2))
ECU
Intercooler assemblyAir cleaner assembly
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3. BASIC INSPECTION
1) Battery Terminal
Make sure the terminal connections are
securely tightened. If the terminals are
corroded, clean them or replace the battery. -
* Cleaning
Remove the corrosion or dirt with a wire brush
or sand paper, and then wash out with
lukewarm soapy water.
2) Measuring the Voltage Drop
Measuring at battery terminal
Measure the voltage between battery
terminal (+. -) and wiring clamp. -
Specified valuebelow 0.3V
If the terminals are corroded, clean and
retightening them. If the specified tightening
torque cannot be kept, replace the clamp.
Terminal (+)
Terminal (-)
Terminal (+): 4 ~ 5 Nm
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1. LAYOUT
D20DTF(Low CO2) D20DTF
ECUBattery sensor (EBS)
Alternator (ALT)
Meter cluster (charge
warning lamp)
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2. OPERATING PROCESS
System diagram
Operation
EEM monitors the electric loads and battery conditions and controls the voltage to improve the fuel
economy and battery charging efficiency.
SOC) to engine ECU with LIN communication.
Engine ECU outputs the information from EBS and regulating control signal (PWM) according to the
Engine ECU controls the magnetic resistance between stator coil and rotor coil by controlling the
current in rotor coil according to PWM duty value.
The alternating voltage induced to stator coil is converted to direct voltage by rectifier. And, EBS
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