2012 SSANGYONG NEW ACTYON SPORTS Service Manual

10-4
Glow plug control unit
(GCU)
1. OVERVIEW
The pre-heating system for D20DTR engine has the glow plug to the cylinder head (combustion
chamber), and improves the cold start performance and reduces the emission level.
The pre-heating resistor (air heater) is used to heat the intake air.
This enables the diesel fuel to be ignited in low temperature condition.
The ECU receives the information such as, engine rpm, coolant temperature, engine torque, etc.,
through CAN communication during pre-heating process; and the pre-heating control unit
controls the pre-heating, heating during cranking and post-heating by the PWM control.
Glow plug
Glow indicatorEngine ECU (D20DTR)

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2. SYSTEM OPERATION
1) Input/Output Diagram of Glow Plug Control Unit
2) System Diagram

10-6
3) Circuit Diagram

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4) Operation
Glow plug is installed in the cylinder head. It enhances the cold starting performance and reduces
the exhaust gas during cold starting.
(1) Operation
Duty control area:
Between 5 and 100%
Frequency: 20 Hz
Duty ratio = (RMS voltage)²
(Battery voltage)² 1.
2.
3.
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
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47009b008f008c0047008c0095008e00900095008c0047006c>CU before starting.
Pre-
heatingCoolant
temperature-30°C -25°C -20°C -10°C -5°C 0°C 20°C
Operating time
28 s 25 s 15 s 5 s 2 s 2 s 0 s
Operating
conditions- IGN: ON
- B+: below 15.2 VStop
conditions- Time-out
- IGN: OFF
- when engine cranking
If the input power (VB) is 11.5 V or less, the GCU supplies the battery power for arrival time
(T1).
If the input power (VB) is greater than 11.5 V, the GCU supplies the voltage of 11.5 V for arrival
time (T1). 1.
2.
- The time for pre-heating is controlled by the ECU.
The time for pre-heating by coolant temperature can vary slightly depending on e.g. other
vehicle operation elements.

10-8
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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8c0047009b00960047005800530058005700570b450055>
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.
At 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 pre-heating
request from the engine ECU.
Post-
heatingOperating time
(approx.)-20°C -10°C 0°C 20°C 80°C
Operating time
(approx.)100 s 50 s 25 s 10 s 10 s
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 preheat (Step 3) for 30 seconds.
P1 to P2: Pre glow
P3 to P4: Post glow

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1. SPECIFICATION
Description Specification
Capacity 12 V, 2.3 kW
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

11-4
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

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1. SYSTEM DESCRIPTION
The starter (start motor) starts the engine with rotational power by converting the electric energy
to the mechanical energy.
When the engine is cranking, the pinion gear meshes with the ring gear. If the ring gear overruns,
the pinion gear clutch overruns to protect the pinion gear.
2. OPERATING PROCESS
1) System Layout