SsangYong Korando III (2010 year). Manual - part 78

15-34

Coolant temp. 

sensor

(8) Cooling fan control

a. Overview of cooling fan and A/C compressor

The cooling system maintains the engine temperature at an efficient level during all engine operating 

conditions. The water pump draws the coolant from the radiator. The coolant then circulates through 

water jackets in the engine block, the intake manifold, and the cylinder head. When the coolant reaches 

the operating temperature of the thermostat, the thermostat opens. The coolant then goes back to the 

radiator where it cools. The heat from automatic transaxle is also cooled down through the radiator by 

circulating the oil through the oil pump. 

There are two cooling fans (200W+150W) in D20DTF engine. ECU controls the electric cooling fans 

with three cooling fan relays to improve the engine torque and air conditioning performance.

For details about A/C compressor and refrigerant pressure sensor, refer to Chapter "Air Conditioning 

System" in "Body" section.

b. Components

Refrigerant pres. 

sensor

A/C compressor

ECU

D20DTF 

DSI 6 A/T

(ATF temp.)

Cooling fan module

HFM sensor

(Intake air 

temperature)

Engine room 

relay box

15-35

0000-00

c. Input/Output for cooling fan and A/C compressor

15-36

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 fan

Coolant temperature

Refrigerant pressure

A/C 

compressor

OFF 

OFF 

Coolant temp. < 90℃

- 

LO 

90℃ ≤ Coolant temp. 

 < 105℃

- 

HI

105℃ ≤ Coolant temp

- 

ON

LO

Coolant temp.  < 105℃

Refrigerant pressure < 

18 bar

ON

HI

18 bar ≤ Refrigerant 

pressure 

HI

105℃ ≤ Coolant temp.  

< 115℃

- 

HI

115℃ ≤ Coolant temp. 

- OFF 

(cut)

A/C compressor OFF conditions

▶

Coolant temperature: below -20℃ or over 
115℃

Approx. 4 seconds after starting the engine

Engine rpm: below 650 rpm or over 4500 rpm 

When abrupt acceleration

Refrigerant pressure:
* OFF below 2.0 kg/㎠, then ON over 2.4 kg/㎠ 
* OFF over 30 kg/㎠, then ON below 21.4 kg/㎠

-

-

-

-

-

The output voltage from refrigerant pressure sensor is 1.7 V to 3.5 V when the refrigerant pressure is 10 
to 24 kgf/㎠ with A/C "ON".

Output voltage according to refrigerant pressure

▶

Cooling fan control according to ATF temperature

▶

ATF temperature

Cooling fan

Remark

Over 100˚C

High speed

-

15-37

0000-00

HFM

(Intake air temp.)

Coolant temp. 

sensor

(9) 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

PTC heater

D20DTF

ECU

Engine room relay box

A: PTC 1 (changeable)

B: PTC 2,3 (not changeable)