SSANGYONG NEW REXTON 2012 Service Manual
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D.  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)
-
-
-
-
-
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.
For details, refer to Chapter "Immobilizer". 
B. Components
Basic components (ignition key system)
D20DTR ECUImmobilizer antennaInstrument cluster
Immobilizer keyStart motor 
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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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(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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Diff. pres. sensor: Measure 
pressure between front 
side 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 
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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E. Cautions
Use only specified Engine Oil (approved by MB Sheet 229.51) for CDPF. -
Use only specified engine oil (Low Ash Oil)
The vehicle equipped with CDPF should use specific engine oil to improve the engine performance 
and fuel economy, and ensure the service life of CDPF. -
Issue with normal engine oil
Sulfur, one of the contents of engine oil is burned and generates soot that is not regenerated by the 
DPF. This remains on the filter as ashes and keeps accumulating. Eventually, this ashes will block 
the filter. -
Benefit for specified engine oil
Minimized the sulfur content of engine oil which reduces the service life.
Improved fuel economy and emission level of CO2 with high performance and low viscosity.
Increased service life of engine oil with high resistance to temperature. -
-
-
Problems when using unspecified engine oil
The service life of filter may be reduced by 30% or more by the ashes accumulated on the filter.
The fuel economy may be reduced because of engine rolling resistance, frequent regeneration of 
DPF. -
-
These problems are also caused by oil with high sulfur content, such as tax exemption oil and 
heating oil, etc. * 
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3) Input/Output for CAN communication
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1. STRUCTURE AND COMPARISON
D27DT (EU IV) Engine - Front View
D27DT (EU IV) Engine - Top View 
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D27DT (EU IV) Engine - Side View
D27DT (EU IV) Engine - Left Side View