Page 478 of 600
D. Cooling fan and A/C compressor control
Conditions for cooling fan
The cooling fan module controls the cooling fan relay, high speed relay and low speed relay. The cooling
fan is controlled by the series and parallel circuits.
A/C switch Cooling fanCoolant temperature Refrigerant pressure
A/C
compressor
OFF OFF
-
LO
-
HI
-
ONLO
Refrigerant pressure <
18 bar
ON
HI
pressure
HI
-
HI
-
OFF (cut)
A/C compressor OFF conditions
Approx. 4 seconds after starting the engine
Engine rpm: below 650 rpm or over 4500 rpm
When abrupt acceleration
Refrigerant pressure:
-
-
-
-
-
The output voltage from refrigerant pressure sensor is 1.7 V to 3.5 V when the refrigerant pressure is 10
Output voltage according to refrigerant pressure
Cooling fan controls according to ATF
ATF temperature Fan condition Remark
High speed -
Page 479 of 600
0000-00
(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
sensorPTC heaterD20DTR ECU
PTC 1 relay
PTC 2 relay
PTC 3 relay
PTC Fuse 3 (40A)PTC Fuse 2 (40A)PTC Fuse 1(40A)
Relay box in engine compartment
Page 481 of 600
0000-00
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) -
-
-
-
-
Page 509 of 600

0000-00
3) Guidelines on Engine Service
To prevent personal injuries and vehicle damages that can be caused by mistakes during engine
and unit inspection/repair and to secure optimum engine performance and safety after service
works, basic cautions and service work guidelines that can be easily forgotten during engine
service works are described in.
Cautions before service works
For safe and correct works, you must observe the working procedures and instructions in this
manual. And, use the designated tools as follow:
Engine stand / Heavy duty engine jack
To prevent the engine from starting abruptly, do not allow anybody to get in the vehicle while
servicing in engine compartment.
Before work on engine and electrical equipment, be sure to disconnect battery negative (-)
terminal.
Before service works, be sure to prepare the works by cleaning and aligning work areas.
Do not allow the foreign material get into the fuel injection system.
When removing the engine, use only the safety hook on engine and engine hanger. Do not
support the bottom of oil pan with a jack. -
-
-
-
-
Completely drain the engine oil, coolant and fuel from engine before removal.
Before disassembling/assembling the engine components, carefully read the working
procedures in this manual.
Make sure to keep the specified tightening torques during installation.
Clean and properly lubricate the parts before reassembly.
Carefully check that there is not any interference while servicing. -
-
-
-
-
Page 514 of 600
Engine Compartment Layout
Engine assembly
Engine oil dipstick
Vacuum pump
Oil filter and cooler
Fuel filter and priming pump
Brake booster
Brake oil tank
AQGS unit
Washer fluid filler cap
Engine compartment fuse box
PTC relay box
Battery
Vacuum modulator (for VGT turbo charger) 1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.FFH Assembly (Only for vehicle with FFH)
Power steering oil tank
Engine oil filler cap
Fan shroud
E-EGR Valve
High-capacity PCV oil separator
HFM sensor (6.0)
VGT turbo charger
Air cleaner housing
2Coolant surge tank
ABS/ESP HECU (Including TPMS function:
optional)
Exhaust gas FRT Temp. sensor (T3) 14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
Page 525 of 600
1212-01
1. D27DT ENGINE STRUCTURE
1) Major Components in Engine and Engine Compartment
The advanced electronically controlled D27DT engine that has high pressure fuel system has
been introduced to this vehicle. It satisfies the strict emission regulation and provides improved
output and maximum torque.
1. Coolant reservoir
2. FFH device
3. Brake fluid reservoir
4. Washer fluid reservoir
5. Common rail6. Fuse box
7. Battery
8. Fuel filter
9. Power steering pump
10. Priming pump11. EGR valve
12. Air cleaner assembly
13. Turbo charger
14. Oil dipstick
Page 526 of 600
2) Engine Structure
1. TVD (Torsional Vibration Damper)
2. Air conditioner compressor
3. Power steering pump pulley
4. Idle pulley
5. Coolant pump pulley
6. Alternator7. Viscos fan clutch
8. Auto tensioner pulley
9. Auto tensioner
10. Poly-grooved belt
11. Cam position sensor
12. Drive plate (MT: DMF)13. Oil filter
14. Vacuum pump
15. Crank position sensor
16. EGR valve
17. Power steering pump
18. EGR to center pipe
Front View
Rear View
Page 555 of 600
1520-01
1. COMPARISON IN COOLING SYSTEM FOR EACH ENGINE
For the D27DTP (POWER UP) engine, the cooling system is equipped with E-EGR cooler and the
water pump which its capacity is improved according to the additional coolant line in the cylinder
block. For the D27DT engine, the cooling system uses the fan clutch.
Cooling System for D27DTP (POWER UP) Engine