2012 SSANGYONG RODIUS Service Manual

15-36
C. Input/Output for oxygen sensor

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D. Oxygen sensor control
The wide band oxygen sensor uses ZnO2. It produces the voltage by movement of oxygen ions when
there is oxygen concentration difference between exhaust gas and atmosphere.
If a certain voltage is applied to the sensor, the movement of oxygen ions occurs regardless of the
oxygen density. The current generated through this flow of ions, is called pumping current (IP), and the
oxygen sensor measures this value.

15-38
Relay box
A/C
compressorHFM (intake air
temperature)Cooling fan
module
MB 5 A/T (ATF
temperature)Coolant
temperature
sensor
(12) 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 transmission is also cooled down through the radiator
by circulating the oil through the oil pump. ECU controls the electric cooling fans with three cooling fan
relays to improve the engine torque and air conditioning performance.
For detailed information, refer to Chapter "Air Conditioning System".
B. Components
D20DTR ECU
Refrigerant

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

15-40
D. Cooling fan and A/C compressor control
Conditions for cooling fan control ▶
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 -
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% -
PWM cooling fan control according to A/C refrigerant pressure -
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 ▶
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 -
-
-
-
-
-
-

15-42
(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
PTC Fuse and Relay

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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
<006a00960096009300880095009b0047009b008c00940097008c00990088009b009c0099008c004702fb00470058005c00b6006a006100470077007b006a00470076007500470088008d009b008c00990047009a0088009b0090009a008d00a00090009500
8e0047009b008f008c0047008a00960095008b0090009b0090>ons in 2nd step -
-
2nd step (coolant temperature ≥ 15°C) ▶
<006a00960096009300880095009b0047009b008c00940097008c00990088009b009c0099008c004702fa0047005d005c00b6006a004700880095008b004700900095009b00880092008c00470088009000990047009b008c00940097008c00990088009b00
9c0099008c004702fa004700540058005700b6006a00610047>PTC ON
<006a00960096009300880095009b0047009b008c00940097008c00990088009b009c0099008c004700630047005d005700a5005d005c00b6006a004700880095008b004700900095009b00880092008c00470088009000990047009b008c00940097008c00
990088009b009c0099008c00470063004700540058005700a5>0°C: PTC ON
<006a00960096009300880095009b0047009b008c00940097008c00990088009b009c0099008c004702fa0047005d005700b6006a004700880095008b004700900095009b00880092008c00470088009000990047009b008c00940097008c00990088009b00
9c0099008c004702fa0047005700a5005c00b6006a00610047>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) -
-
-
-
-