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03-6
2) Diagnostic Test for Engine Fuel System
(1) Overview
If a DTC is displayed on the diagnostic device, check the low pressure- and high pressure fuel
systems before removing the components.
To run the system properly, the electric system must be intact but for the DI engine, the fuel
pressure should be measured also when there is a malfunction even after the diagnostic test with
a diagnostic device.
(2) Hydraulic system
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03-8
(4) Loss of pump pressure/flow
Loss of HP pump pressure/flow ▶
Faulty fuel supply line, or damaged or worn pump causes the lack of flow pressure and flow
volume
Example: ▶
Air in fuel supply line
Excessive load on fuel supply line (←400 mBar)
Burned out and mechanical worn pump
High temperature of fuel supply (> 85℃) -
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03-92210-01
3) DI Engine Fuel System Pressure Test
(1) Test device (Tool kit)
Device for high pressure
Device for low pressure
(2) Pre-check
Check-tighten fuel supply line
Check fuel level in fuel tank
Check air in fuel supply line (bubble in fuel supply line or fuel)
Check fuel supply line for leaks (low pressure and high pressure)
Check that specified fuel is used
Check fuel filter for contamination -
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03-10
(3) DI Engine Fuel System Check Procedure
If several DTCs are output simultaneously, check the electric wiring for open or short circuit.
Check the low pressure fuel system and fuel filter and confirm that there are no abnormalities.
Carry out the high pressure fuel system check.
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03-112210-01
(4) Fuel System Check Procedure
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03-12
(5) High Pressure System Pressure Test
Fuel rail pressure test ▶
Disconnect the fuel rail pressure sensor
connector and then IMV connector. 1.
Connect the pressure tester to the fuel rail
pressure sensor connector. 2.
Crank the engine 2 times for 5 seconds. 3.
Read the highest pressure value
displayed on the tester display.
If the highest pressure value is 1,050 bar
or less, refer to the section "Fuel System
Check Process". -
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03-132210-01
How To Use Pressure Tester ▶
Press the "TEST" button on the tester to
check if the message "TEST?" is
displayed.
If the button is pressed again at 4 seconds
after starting engine cranking, the highest
pressure is displayed on the tester. 1.
2.
The fuel rail pressure value can be checked using a diagnostic device.
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03-14
(6) Low Pressure System Pressure Test
Inspection procedure ▶
All wirings/connectors and fuel lines should
be connected and the engine should work
properly.
Prepare a special tool for low pressure test
and clean it thoroughly to prevent foreign
materials from entering. 1.
2.
Disconnect the key connector for fuel filter connection, and connect both connectors to the
fuel filter and hose. 3.
Start the engine and check visually for clogged low pressure fuel system, excessive air or air
entry.
If the fuel flow is not sufficient or air is in the fuel, repair the leak area. 4.
5.