SsangYong Korando III (2010 year). Service manual - part 71

15-6

2. SYSTEM OPERATION

1) Input/Output of ECU

(1) ECU Block diagram

15-7

0000-00

Fuel rail 

pres.sensor

Differential 

pressure 

sensor

Swirl valve posi. 

sensor

Meter cluster

Coolant temp. 

sensor

E-EGR valve 

posi. sensor

Oxygen 

sensor

Exhaust gas 

temp. sensor

HFM sensor

(2) Components for ECU Input

Crankshaft posi. 

sensor

Accel. pedal 

posi. sensor

Throttle 

posi.sensor

Knock sensor

T-MAP sensor

Camshaft posi. 

sensor

CAN

- ABS&ESP
- GCU
- Meter cluster
- TCU
- BCM

- Refrigerant pressure sensor
- Clutch pedal signal
- Blower switch signal
- Brake pedal signal

Oil level sensor

15-8

Engine room 

relay box

E-EGR valve

Cooling fan

E-EGR cooler 

bypass valve

E-VGT 

actuator

IMV

Throttle posi. 

sensor

Injector

A/C 

compressor

Start motor

Variable swirl 

valve

(3) Components for ECU Input

PTC heater

CAN

- Glow plug unit
- ABS & ESP unit
- BCM
- E-coupling unit
- EPS
- GCU
- Meter cluster
- SKM
- TCU
- Self diagnosis

15-9

0000-00

2) ECU Control

(1) Function

a. ECU Function

ECU receives and analyzes signals from various sensors and then modifies those signals into 

permissible voltage levels and analyzes to control respective actuators.

ECU microprocessor calculates injection period and injection timing proper for engine piston speed and 

crankshaft angle based on input data and stored specific map to control the engine power and emission 

gas.

Output signal of the ECU microprocessor drives pressure control valve to control the rail pressure and 

activates injector solenoid valve to control the fuel injection period and injection timing; so controls 

various actuators in response to engine changes. Auxiliary function of ECU has adopted to reduce 

emission gas, improve fuel economy and enhance safety, comforts and conveniences. For example, 

there are EGR, booster pressure control, autocruise (export only) and immobilizer and adopted CAN 

communication to exchange data among electrical systems (automatic T/M and brake system) in the 

vehicle fluently. And Scanner can be used to diagnose vehicle status and defectives.
Operating temperature range of ECU is normally -40 to +85°C and protected from factors like oil, 

water and electromagnetism and there should be no mechanical shocks.

To control the fuel volume precisely under repeated injections, high current should be applied instantly 

so there is injector drive circuit in the ECU to generate necessary current during injector drive stages.

Current control circuit divides current applying time (injection time) into full-in-current-phase and hold-

current-phase and then the injectors should work very correctly under every working condition.

b. Control Function

Controls by operating stages

To make optimum combustion under every operating stage, ECU should calculate proper injection 

volume in each stage by considering various factors.

Starting injection volume control

During initial starting, injecting fuel volume will be calculated by function of temperature and engine 

cranking speed. Starting injection continues from when the ignition switch is turned to ignition 

position to till the engine reaches to allowable minimum speed.

Driving mode control

If the vehicle runs normally, fuel injection volume will be calculated by accelerator pedal travel and 

engine rpm and the drive map will be used to match the drivers inputs with optimum engine power.

-

-

-