2012 SSANGYONG KORANDO Service Manual

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4) System Operation
Glow plug is installed in the cylinder head. It enhances the cold starting performance and reduces the
exhaust gas during cold starting.
ECU receives the various signals such as engine rpm, coolant temperature and vehicle speed through
CAN communication lines. GCU controls the pre-heating, cranking and post-heating operations and
monitors the glow plug. If GCU detects a problem, it sends the result to ECU.
(2) Operation of AQGS
Duty control area:
Between 5 and 100%
Frequency: 20 Hz
Duty ratio = (RMS voltage)²
(Battery voltage)² 1.
2.
3.
(1) Characteristics of temperature and current in AQGS
AQGS unit increases the glow plug temperature very rapidly (1,000˚C in 2 seconds).
FET (similar to transistor) for each cylinder in AQGS unit pre-heats the glow plug.
If the glow plug temperature reaches to target temperature, the temperature is controlled by
duty ratio. 1.
2.
3.
AQGS PWM ControlActual voltage pattern
AQGS unit supplies the power to glow plug. This shows the voltage and time
supplied by AQGS by steps. As shown
on the graph, the supplied voltage is
decreased as the steps are continued.
The 3rd step is to keep the temperature,
not to raise it.
Frequency: 20~33Hz
PWM Control duty ratio
- 1st step: 100%
- 2nd step: 35%
- 3rd step: 23%

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(3) Operating Steps
Pre-Glow: Step 1 ▶
If normal communication with the ECU is established 2 seconds after the power is supplied to the IGN
terminal from the battery, the GCU supplies the battery power to raise the temperature of the glow plug
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47006c006a007c00470089008c008d00960099008c0047009a>tarting.
- The time for pre-heating is controlled by the ECU.
If the input voltage (VB) is 11.5 V or less, GCU supplies the battery voltage for preheating time (T1).
If the input voltage (VB) is greater than 11.5 V, GCU supplies the voltage of 11.5 V for preheating time
(T1). -
-
The preheating time may vary according to the conditions.
Input voltage
VB (V)Pre-heating time T1
(sec)
6 8.27
7 5.8
8 4.1
9 3.15
10 2.4
11 1.95
≥ 11.5 1.9

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During cranking: Step 2 and step 3 ▶
Step 2: If the ECU receives the cranking signal after pre-heating (step 1), the GCU supplies the
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Step 3: The GCU supplies the voltage of 5.1 V to keep the temperature at 1,000°C. 1.
2.
Under fixed temperature: The AQGS unit supplies power for 30 seconds (Step 1 + Step 3) if no
cranking signal is received after the step 1.
During cranking: The step 3 is started after the step 2. *
*
Post-glow: Step 4: ▶
The post-heating is for reducing HC/CO after the engine is started. If the time for post-heating exceeds
180 sec., the GCU unit cuts off the power to each glow plug even if there is preheating request from the
engine ECU.
Emergency glow ▶
If no CAN signal is received for 4 seconds from the engine ECU after the IGN ON signal is input, the
GCU performs emergency preheating (Step 3) for 30 seconds.

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Normal operating mode ▶
This shows the components of preheating system in the pre-heating and the post-heating steps.

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When there is no engine cranking signal after turning the ignition key ON ▶

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1. SPECIFICATION
Capacity 12V 2.3kW
Engagement Meshed type
Rotating direction Clockwise
Pinion gear manufacturing Cooled forging
Solenoid operating voltage Max. 8 V
Weight 2.5 kg
Bracket manufacturing Aluminum die casting

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2. TROUBLESHOOTING
ProblemPossible Cause　　Action
Engine will not crankLow battery voltage Charge or replace
Loose, corroded or damaged battery cable
Repair or replace
Faulty starter or open circuit
Faulty ignition switch or blown fuse Repair or replace
Poor engine ground Repair
Engine cranks too
slowLow battery voltage Charge or replace
Loose, corroded or damaged battery cable
Repair or replace
Faulty starter
Starter does not
stopFaulty starter
Faulty ignition switch Replace
Engine cranks
normally, but does
not startBroken pinion gear or faulty starter
Replace the starter
Broken flywheel ring gear Replace
Open circuit Repair