SsangYong Rodius (2013 year). Manual - part 92

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

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D. Cooling fan and A/C compressor control

 Conditions for cooling fan control

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The PWM cooling fan is set by coolant temperature and A/C refrigerant pressure. And, the setting 

value in A/T equipped vehicle may vary according to the internal oil temperature. The The engine ECU 

controls the PWM cooling fan unit based on various signals to get the optimized temperature during 

engine running.

PWM cooling fan control according to coolant temperature and vehicle speed

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The PWM cooling fan starts running 
from 89℃ of coolant temperature

PWM cooling fan control according to transmission fluid temperature (A/T)
1. PWM duty under 129℃: 0%
2. PWM duty over 130℃: 94.4%

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PWM cooling fan control according to A/C refrigerant pressure 

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PWM duty value sharply increases 

when the A/C refrigerant pressure 

goes over 10 bar. And, it slowly 

decreases when A/C refrigerant 

pressure goes down below 14 bar 

(A/C compressor OFF).

PWM duty

Refrigerant 

pressure (bar)

under 101℃: The PWM duty value

decreases when the vehicle speed 

increases
over 105℃: The PWM duty value 

is fixed at 94.4%

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A/C compressor OFF conditions

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Coolant temperature: 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