Page 148 of 198
13B-148V4 MR-372-J84-13B000$120.mif
DIESEL INJECTION
Fault finding – Tests13B
DDCR INJECTION
Vdiag No.: 44, 48
TEST 1 Low pressure circuit check
Check the conformity of the low pressure circuit
connections
Are the low pressure circuit connections correct? Carry out the necessary repairs.
Check the condition of the priming bulb, and that it is
working properly.
Look for leaks at the unions.
Are there leaks from the hoses and unions? Carry out the necessary repairs
Check that there are no air bubbles in the diesel fuel. Bleed the low-pressure circuit.
Place a container under the filter.
Disconnect the return hose from the filter and
plug the filter.
Pump using the priming bulb until there is no air
left.
Reconnect the return hose immediately. Are air bubbles present in the low pressure circuit?
Low pressure circuit correct.
NO
YES
YES
NO
YES
NO
DDCR_V44_TEST01/DDCR_V48_TEST01
Page 150 of 198
13B-150V4 MR-372-J84-13B000$120.mif
DIESEL INJECTION
Fault finding – Tests13B
DDCR INJECTION
Vdiag No.: 44, 48
TEST 3 Injector check
Is diesel fuel present around the injectors?Locate the source of the leak and carry out the
necessary repairs.
Control the injectors with the commands
AC005 Cylinder 1 injector,
AC006 Cylinder 2 injector,
AC007 Cylinder 3 injector,
AC008 Cylinder 4 injector.Check the insulation and the continuity of the
electrical circuit.
Run test 9 Diesel filter check.
If test 9 is correct, replace the faulty injectors (MR 364
(Mégane II) or MR 370 (Scénic II), Mechanical, 13B,
Diesel injection, Diesel injector: Removal -
Refitting). Can you hear the valve moving when you are
1metre away from the vehicle?
End of TEST 3.YES
NO
NO
YES
DDCR_V44_TEST03/DDCR_V48_TEST03
Page 151 of 198
13B-151V4 MR-372-J84-13B000$120.mif
DIESEL INJECTION
Fault finding – Tests13B
DDCR INJECTION
Vdiag No.: 44, 48
TEST 5 Inlet circuit check
Check for air leaking in or out.
Is air leaking in or out? Carry out the necessary repairs
Check the condition of the air filter. Replace the air filter (see MR 364 (Mégane II) or
MR 370 (Scénic II), Mechanical, 12A, Fuel
mixture, Air filter, Removal - Refitting). Is the air filter in order?
Check that the inlet manifold is not obstructed
(clogged).
Is the inlet manifold blocked? Clean the inlet manifold.
Air system in good order.
YES
NO
NO
YES
YES
NO
DDCR_V44_TEST05/DDCR_V48_TEST05
Page 152 of 198

13B-152V4 MR-372-J84-13B000$120.mif
DIESEL INJECTION
Fault finding – Tests13B
DDCR INJECTION
Vdiag No.: 44, 48
IMV = fuel flow actuator
TEST 6 High pressure system check
NOTESSpecial note:
Certain faults make it impossible to carry out this test - deal with these first.
IMPORTANT: It is pointless and dangerous to engage the starter motor for more
than 5 seconds.
Preliminary Checks:
– Check for the presence of fuel
– Check that there is no air in the low pressure circuit. Run TEST 1: Low pressure circuit check.
– Ensure that the correct fuel is being used. Run TEST 13 Diesel fuel conformity check.
It is possible to check the high pressure supply pump capacity by carrying out the following procedure:
–With the ignition off, disconnect the low pressure actuator from the pump (IMV brown connector) and connect
a test IMV or the MOT. 1711 adapter.
– Electrically disconnect the four injectors.
– Switch on the ignition, connect the diagnostic tool and re-establish dialogue with the injection system.
– Go to the Main computer statuses and parameters screen.
– Run the test cold, PR064 Coolant temperature < 30°C or equal to the ambient temperature.
– Engage the starter for 5 seconds.
– Read the rail pressure maximum value (PR038) during the test on the diagnostic tool.
Is the rail pressure greater than 1050 bar?
A
NO
B
YES
DDCR_V44_TEST06/DDCR_V48_TEST06
Page 153 of 198

13B-153V4 MR-372-J84-13B000$120.mif
DIESEL INJECTION
Fault finding – Tests13B
DDCR INJECTION
Vdiag No.: 44, 48
TEST 6
CONTINUED
– Switch off the ignition, reconnect the electrical
connections to the four injectors and the low-
pressure actuator.
– Switch on the ignition again, and clear the
injection faults using the diagnostic tool.
– Check if there is no fuel leak in the high pressure
circuit. Run TEST 7 High pressure circuit
sealing check
– Check the conformity of the diesel filter. Run
TEST 9 Diesel filter check.
– Carry out fault finding on the injectors by
checking the return flow volume of the four
injectors, run TEST 8 Injector return flow.
–Is TEST 8 OK?The pump can supply the operating pressure.
Switch off the ignition, reconnect the electrical
connections
to the four injectors and the low pressure actuator.
Switch on the ignition again, and clear the injection
faults using the diagnostic tool.
Check if there is no fuel leak in the high pressure
circuit. Run TEST 7 High pressure circuit sealing
check.
Carry out fault finding on the injectors by checking the
return flow volume of the four injectors, run TEST 8
Injector return flow.
If TEST 8 is correct, the high pressure fuel circuit is
correct.
Replace the faulty injectors
(see MR 364 (Mégane II) or
MR 370 (Scénic II),
Mechanical, 13B, Diesel
injection, Diesel injector:
Removal - Refitting)Replace the high pressure pump (see MR 364 (Mégane II) or MR 370
(Scénic II), Mechanical, 13B, Diesel injection, High pressure pump:
Removal - Refitting).
A
NO
B
YES
NOYES
Page 157 of 198

13B-157V4 MR-372-J84-13B000$120.mif
DIESEL INJECTION
Fault finding – Tests13B
DDCR INJECTION
Vdiag No.: 44, 48
TEST 8
CONTINUED 2
If the engine does not start, only the static leak can be measured, that is the leak with the injector closed, not being
actuated and under high pressure.
Make sure that the ignition circuit is working correctly (minimum engine speed 200 rpm).
Tooling required
– Mot. 1711 Injector flow measuring kit.
Or: Use four tubes of internal diameter 4 mm and approximately 50 cm long and a test adapter (TEST IMV).
Procedure
– Switch off the ignition,
– disconnect the return pipes from the four injectors,
– cap the pump venturi tube to prevent the low-pressure circuit from depriming,
– connect the four transparent pipes in place of the return pipes (Mot. 1711),
– disconnect the low pressure actuator from the pump (brown IMV connector) and connect a test IMV or the
adapter of Mot. 1711,
– electrically disconnect the four injectors,
– switch on the ignition and engage the starter for 5 seconds,
– measure the amount of diesel fuel in each pipe.
Replace the injectors that have a leak return greater than 10 cm.
Switch off the ignition, and reconnect the four injectors electrically.
Disconnect the test IMV and reconnect the low-pressure actuator connector to the pump. Disconnect the
four transparent tubes and reconnect the injectors return circuit. Switch on the ignition again, and clear the injection
faults using the diagnostic tool.
A
NO
Page 159 of 198

13B-159V4 MR-372-J84-13B000$120.mif
DIESEL INJECTION
Fault finding – Tests13B
DDCR INJECTION
Vdiag No.: 44, 48
TEST 9 Diesel filter check
Check the conformity of the diesel filter. Replace the filter with an original part (see MR
364 (Mégane II) or MR 370 (Scénic II),
Mechanical, 13A, Fuel supply, Fuel filter:
Removal - Refitting) Is the diesel filter in order?
– Switch off the ignition and analyse the diesel fuel in the diesel filter.
– Disconnect the diesel supply and return hoses from the filter.
– Block the filter inlets and outlets straight away with appropriate plugs.
– Remove the filter from its holder and shake it firmly while holding the caps in place. Tap the edge of the filter
with a screwdriver handle to detach any contamination. Empty the contents of the filter into a glass container by
lifting a protective plug, then loosening and completely removing the bleed screw.
Is there a deposit of black particles at the bottom of the container?
Pass a magnet beneath the container to collect
all the metal particles. Take the magnet away
from the container.Diesel filter in good order.
Do the particles collected, using the magnet,
cover a surface area greater than 1 cm
2?
Replace the entire injection system Diesel filter in good order.
NO
YES
YESNO
YES
YES
DDCR_V44_TEST09/DDCR_V48_TEST09
Page 160 of 198

13B-160V4 MR-372-J84-13B000$120.mif
DIESEL INJECTION
Fault finding – Tests13B
DDCR INJECTION
Vdiag No.: 44, 48
TEST 11 Turbocharger air chain
Check for the air filter
Check the replacement interval of the air filter on the maintenance booklet.
Compare the part numbers of the air filter fitted to the vehicle and that of the air filter recommended by the
manufacturer.
Check the air filter direction of fitting.
Is the air filter fitted to the vehicle correct?
Check the condition of the air filter
Visually inspect the condition of the filtering section of the air
filter.
Is either the air filter or its seal damaged?
Is the air filter fouled (does it contain a lot of impurities)?Replace the air filter (see MR 364
(Mégane II) or 370 (Scénic II),
Mechanical, 12A, Fuel mixture, Air
filter, Removal - Refitting).
Low pressure circuit check
Note:
Depending on the vehicle type, the best visual access will be
either from above or from below.
Visually inspect the condition of the following components:
– fresh air inlet scoop on the front panel of the vehicle,
– air inlet pipe to the air filter,
– air pipe of the filter until the compressor inlet,
– mountings of the air flowmeter.
Is one of these components incorrect (disconnected,
cut, bent, pierced or kinked pipes)?Replace the defective parts (see MR
364 (Mégane II) or 370 (Scénic II),
Mechanical, 12B, Turbocharging).
YESNO
YES
NO
YES
A
NO
DDCR_V44_TEST11/DDCR_V48_TEST11