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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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15-48
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
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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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No. FUNCTION No. FUNCTION
1 HFM sensor 12 Intake manifold
2 Intake air duct 13 Connecting rod
3 Resonance flap 14 Exhaust manifold
4 Cylinder head cover 15 Crankshaft
5 Exhaust camshaft 16 Engine mounting
6 Intake camshaft 17 Starter
7 Cylinder head 18 Crankcase
8 Spark plug connector 19 Oil pump sprocket
9 Valve tappe
t20 Oil strainer
10 Injector 21 Oil pan
11 Exhaust valve 22 Drain plug
Front View ▶
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2. DESCRIPTION AND OPERATION
1) Cleanliness and Care
An automobile engine is a combination of many machined, honed, polished and lapped surfaces with
tolerances that are measured in the ten-thousandths of an inch. When any internal engine parts are
serviced, care and cleanliness are important. A liberal coating of engine oil should be applied to friction
areas during assembly, to protect and lubricate the surfaces on initial operation.
Proper cleaning and protection of machined surfaces and friction areas is part of the repair procedure.
This is considered standard shop practice even if not specifically stated.
Whenever valve train components are removed for service, they should be kept in order.
They should be installed in the same locations, and with the same mating surfaces, as when they were
removed. Battery cables should be disconnected before any major work is performed on the engine.
Failure to disconnect cables may result in damage to wire harness or other electrical parts.
2) On-Engine Service
Disconnect the negative battery cable before removing or installing any electrical unit, or when a
tool or equipment could easily come in contact with exposed electrical terminals.
Disconnecting this cable will help prevent personal injury and damage to the vehicle.
The ignition must also be in LOCK unless otherwise noted.
Notice Any time the air cleaner is removed, the intake opening -
Any time the air cleaner is removed, the intake opening should be covered. This will protect
against accidental entrance of foreign material, which could follow the intake passage into the
cylinder and cause extensive damage when the engine is started. -