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A/C compressor OFF conditions ▶
Coolant tem
perature: below -20℃ or over
115℃
Engine rpm: over 4500 rpm
Engine rpm: below 600 rpm
When abrupt acceleration
Very high load during idling
Refrigerant pressure: over 32 bar or below 2
bar
Failure in refrigerant sensor, coolant
temperature sensor, and cooling fan -
-
-
-
-
-
-
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PTC Fuse and Relay
(13) PTC heater control
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
sensor
PTC relay 1
D20DTR ECU
PTC relay 2
PTC fuse 1, 2, 3, 40A
PTC heater
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C. PTC operation process
The PTC operating condition (ON) is controlled in two steps.
Basically, the engine ECU controls the relay to supply the power to PTC according to the coolant
temperature sensor and ambient temperature sensor.
1st step (initial operation of PTC) ▶
Coolant temperature < 15°C: PTC ON
Coolant temperature ≥ 15°C: PTC ON after satisfying the conditions in 2nd step -
-
2nd step (coolant temperature ≥ 15°C) ▶
Coolant temperature ≤ 65°C and intake air temperature ≤ -10°C: PTC ON
Coolant temperature < 60~65°C and intake air temperature < -10~0°C: PTC ON
Coolant temperature ≤ 60°C and intake air temperature ≤ 0~5°C: PTC ON -
-
-
Stop (OFF) conditions ▶
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) -
-
-
-
-
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(14) Immobilizer control
A. 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.
B. Components
Basic components (ignition key system) ▶
D20DTR ECUImmobilizer antennaIndicator/Warning Lamp
Start motorImmobilizer key
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C. 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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(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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C. Input/Output for CDPF control
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Rear EGT sensor:
Measure DPF temp
Diff. pres. sensor:
Measure pressure
between front side and
rear side of CDPFElectronic throttle
body: Control intake
air mass
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
tem
perature is below 600°C, the amount of fuel injected is increased to raise the temperature. If
the tem
perature is over 600°C, the amount of fuel 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
T-MAP sensor
Intake air
mass
Exceed PM
limitBooster
pressure/
temperaturePost injection
Control intake
air mass