SsangYong Korando III (2010 year). Manual - part 79

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c. Operation process

The ceramic PTC has a feature that the resistance goes up very high at a certain temperature. There 

are three circuits in PTC heater. Only one circuit is connected when PTC1 relay is ON, and two circuits 

are connected when PTC2 relay is ON.
Operation process: reaches at a certain temperature→high resistance→low current→less heat 
radiation→temperature down→high resistance→high current→temperature up

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d. Control conditions

Operation

Operating condition

PTC Heater

HI

(PTC2)

- Coolant temperature < 15℃

PTC  HI ON 

LO

(PTC1)

- Coolant temperature 15℃ ≤ 65℃, intake air 
temperature ≤ -10℃
- Coolant temperature 15℃ < 65 to 60℃, intake air 
temperature <-10℃ to 0℃
- Coolant temperature 15℃ ≤ 60℃, intake air 
temperature ≤ 0℃ to 5℃

PTC  LO ON 

Stop

- 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)

Operation diagram for PTC heater LO (step 2)

▶

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Meter cluster

Immobilizer 

antenna

(10) 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.

For details, refer to Chapter "BCM".

b. Components

Basic components (ignition key system)

▶

Immobilizer key

Start motor

BCM

ECU

D20DTF

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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.