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Oil filter module
Thermostat
When the engine coolant
starts to open (fully open at
flow to the radiator to maintain
the engine temperature.
1. SYSTEM DESCRIPTION
1) Overview
Coolant reservoir
Long life coolant is used.
Water pump
The water pump is driven by the engine drive belt and supplies
the coolant to each area of the engine.
Water pump pulley Impeller vaneSealing
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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.
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2. INSPECTION
1) Alternator Output Test
Item How to check DTC set value / Action
Output
current
B terminal
current
Rotor
coil
resistance
L terminal
voltage
Disconnect the cable connected to the B
terminal on the alternator. Connect one end
of the ammeter to the B terminal and the
other end to the cable connected to the B
terminal.
Measure the maximum output value.
(Maintain the engine speed between 2,500
and 3,000 rpm.)
(Turn the headlamp and all the electrical
switches on.) 1.
2.Pass: If the measured current is 45 A
or higher.
Fail: If the measured current is less
than 45 A.
Check the current of the B terminal. -
-
-
Move the gear selector lever to the
neutral position.
Maintain the engine speed at 2,500 rpm
with the vehicle unloaded.
(Turn all the electrical switches off.) 1.
2.Open circuit: If the measured
current is 5 A or higher. -
Disconnect the negative cable from the
battery.
Remove the B terminal and turn off the
ignition switch.
Measure the resistance between the L and F
terminals with an ohmmeter. 1.
2.
3.Pass: If the measured resistance is
Faulty rotor coil or slip ring: If the
measured resistance is less than 3
-
-
Connect the B terminal wiring.
Measure the voltage with the engine running. 1.
2.Specification: 12.5 V to 14.5 V
Faulty IC regulator or field coil: If
the measured voltage is 14.5 V or
higher. -
-
Disconnect the negative battery cable.
Connect the negative cable again after connecting the ammeter. -
-
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2) Troubleshooting for Alternator
Item Cause Action
Overcharged battery Defective alternator voltage regulator Replace
defective alternator detection wiring Repair or replace
Discharged battery Loose alternator drive belt Adjust the belt tension or replace
Poor connection of related circuit or
open circuitRetighten the loose connection or
repair open circuit
Defective alternator voltage regulator Replace
Terminated battery Replace
Defective ground Repair
Charge warning lamp
does not come on when
turning on ignition switch
with engine stoppedDefective alternator voltage regulator Replace
Open circuit in charge warning lamp,
fuse or wiringReplace or repair the charge
warning lamp or fuse
Defective ignition switch Replace
Defective ground of alternator circuit Repair
Charge warning lamp
does not go off after
starting engineDefective alternator voltage regulator Replace
Corroded or worn battery cable Repair or replace
Loose alternator drive belt
Adjust the belt tension or replace the
belt
Defective wiring harness Repair or replace
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(3) Starting with jumper cable
If the battery is weak or terminated, the battery from another vehicle can be used with jumper cables to
start the engine.
Connecting order
The positive (+) terminal of the discharged battery
The positive (+) terminal of the booster battery
The negative (-) terminal of the booster battery
Connect one end of the other jumper cable to the body of the discharged vehicle, such as the
engine block or a front towing hook. 1.
2.
3.
4.
Starting
Prepare a set of jumper cables.
Place another vehicle that has the same 12 V of power near to the discharged vehicle.
Switch off all electrical accessories for the discharged vehicle.
Apply the parking brake and shift the transaxle to the P position (automatic transaxle) or neutral (N)
position (manual transaxle).
Connect the jumper cables.
Try to start the discharged vehicle while accelerating the engine rpm in the booster vehicle.
Attempt to start the engine with the discharged battery.
After starting the engine, carefully disconnect the jumper cables in the reverse sequence of
connection. 1.
2.
3.
4.
5.
6.
7.
8.
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Battery
It converts the chemical energy to the
electrical energy and supplies power to the
corresponding electric units when starting
the engine.Alternator
The alternator charges the battery and
supplies power to each electric unit by
converting the mechanical energy to the
electrical energy.
1. SYSTEM DESCRIPTION
1) Overview
The charge system is designed to supply electrical energy to the vehicle while driving, and supplies a
constant direct current voltage by converting mechanical rotational movement to electrical energy.
The voltage regulator on the back of the alternator controls the generated voltage in all rotating ranges
and adjusts the system voltage according to the electric load and ambient temperature change.
2) System Layout (Locations)
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1. OVERVIEW
The pre-heating system for D20DTF engine has the glow plug to the cylinder head (combustion
chamber), and improves the cold start performance and reduces the emission level.
The pre-heating resistor (air heater) is used to heat the intake air.
This enables the diesel fuel to be ignited in low temperature condition.
The ECU receives the information such as, engine rpm, coolant temperature, engine torque, etc.,
through CAN communication during pre-heating process; and the pre-heating control unit controls the
pre-heating, heating during cranking and post-heating by the PWM control.
Glow plugGlow plug control unit
(GCU)
Glow indicatorEngine ECU (D20DTF)
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4) System Operation
Glow plug is installed in the cylinder head. It enhances the cold starting performance and reduces the
exhaust gas during cold starting.
ECU receives the various signals such as engine rpm, coolant temperature and vehicle speed through
CAN communication lines. GCU controls the pre-heating, cranking and post-heating operations and
monitors the glow plug. If GCU detects a problem, it sends the result to ECU.
(2) Operation of AQGS
Duty control area:
Between 5 and 100%
Frequency: 20 Hz1.
2.
3.
(1) Characteristics of temperature and current in AQGS
FET (similar to transistor) for each cylinder in AQGS unit pre-heats the glow plug.
If the glow plug temperature reaches to target temperature, the temperature is controlled by
duty ratio. 1.
2.
3.
AQGS PWM ControlActual voltage pattern
AQGS unit supplies the power to glow plug. This shows the voltage and time
supplied by AQGS by steps. As shown
on the graph, the supplied voltage is
decreased as the steps are continued.
The 3rd step is to keep the temperature,
not to raise it.
Frequency: 20~33Hz
PWM Control duty ratio
- 1st step: 100%
- 2nd step: 35%
- 3rd step: 23%