Page 154 of 198
13B-154V4 MR-372-J84-13B000$120.mif
DIESEL INJECTION
Fault finding – Tests13B
DDCR INJECTION
Vdiag No.: 44, 48
The command AC029 High pressure circuit sealing test can locate a leak in the high pressure circuit if a union is
incorrectly fitted or screwed on. This command does not identify a union not tightened to torque.
This command can be used only if the engine temperature is greater than 60ºC.
Watch out for any objects (tool or others) on the sides of the engine housing during the 4 accelerations
(possible vibrations).
Run command AC029, the engine will automatically carry out a cycle of four accelerations to increase the rail
pressure. Check if there are leaks on the high pressure circuit.
TEST 7 High pressure circuit sealing check
NOTESSpecial note:
Certain faults make it impossible to carry out this test - deal with these first.
DDCR_V44_TEST07/DDCR_V48_TEST07
Page 155 of 198

13B-155V4 MR-372-J84-13B000$120.mif
DIESEL INJECTION
Fault finding – Tests13B
DDCR INJECTION
Vdiag No.: 44, 48
TEST 8 Injector return flow
NOTESSpecial note:
Certain faults make it impossible to carry out this test - deal with these first.
Does the engine start?
Command AC029 also checks the return volume of each injector to detect an internal injector leak.
Be careful with any objects (tool or other) on the engine housing during the four cycles of the operation
(possible vibrations).
Tooling required
–Mot. 1711 Injector flow measuring kit.
Or: Use four pipes with internal diameter 4mm and approximately 50 cm in length, and four graduated measuring
cylinders.
Procedure
– Ensure that the engine coolant temperature is above 60°C,
– 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 tubes in place of the return pipes,
– put the other ends of the four pipes into four graduated measuring cylinders.
– After finishing these preparations, start the engine and let it idle for 2 minutes.
Note: This idle time must be respected for the test results to be interpreted correctly.
–Run command AC029 High pressure circuit sealing check
.The engine will automatically carry out a cycle of four accelerations to increase the rail pressure and measure the
internal injector leaks under these conditions.
–Once the cycle is complete, run command AC029 again to obtain a correct reading of the return volume of
each injector.
– Switch off the engine at the end of the cycle.
NOA
YES
DDCR_V44_TEST08/DDCR_V48_TEST08
Page 161 of 198

13B-161V4 MR-372-J84-13B000$120.mif
DIESEL INJECTION
Fault finding – Tests13B
DDCR INJECTION
Vdiag No.: 44, 48
TEST 11
CONTINUED
High 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:
– the compressor outlet pipe to the turbocharging air cooler (the
turbocharging air cooler does not exist for all engines),
– outlet pipe of the turbocharging air cooler to the inlet manifold,
– inlet manifold,
– temperature and pressure sensors.
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).
Exhaust system check
Visually inspect the condition of the following engine sections:
– from the exhaust manifold circuit to the turbocharger turbine,
– from the turbine outlet pipe to the end of the exhaust pipe,
– from the inlet manifold to the EGR valve
– check that the temperature and pressure sensors are
connected.
Do some of these components have black or white marks on
them? Replace the defective parts (see
MR 364 (Mégane II) or 370 (Scénic
II), Mechanical, 12B,
Turbocharging).
Run TEST 10: Turbocharger control solenoid valve check.
A
NO
YES
NO
YES
NO
Page 163 of 198
13B-163V4 MR-372-J84-13B000$120.mif
DIESEL INJECTION
Fault finding – Tests13B
DDCR INJECTION
Vdiag No.: 44, 48
TEST 13
CONTINUED 1
Weigh the diesel fuel and note the fuel weight after subtracting the weight of the empty plastic cup and its cover.
Does the fuel weight fall between the minimum and maximum weights given in the table below?
Calculated weight (g.)
Fuel temperature
(°C)
Min. weight Max. weight
821 846 13
821 846 14
820 845 15
819 844 16
819 844 17
818 843 18
817 842 19
816 841 20
816 841 21
815 840 22
814 839 23
814 839 24
813 838 25
Check the fuel temperature by immersing a thermometer in the plastic cup.
End of test. The fuel is not correct.
If the fuel weight is less than the minimum value then there is petrol in the diesel
fuel.
If the fuel weight is greater than the minimum value then there is oil in the diesel
fuel.
Drain the fuel circuit, including the tank (see MR 364 (Mégane) or 370 (Scénic),
Mechanical, 19C, Tank, Fuel Tank: Draining).
A
NO
YESNO
Page 182 of 198

13B-182
AFTER REPAIRCarry out a road test, then check with the diagnostic tool.
V4 MR-372-J84-13B000$140.mif
DIESEL INJECTION
Fault finding – Fault finding charts13B
InjectionDDCR
Vdiag No.: 44, 48
ALP10
CONTINUED
Check the high pressure pump by running
TEST 6 High pressure system check.The vehicle has entered the "Flow capacity
function" program. This function is activated more
easily when: the external temperature is high, the
fuel level in the tank is at 1/4, the vehicle is laden
and if the vehicle speed is high. Is the "Flow capacity function"
programming active (ET563)?
Check the computer:
Check that the computer connectors are
properly locked.
Check the condition of the computer
connections (bent pin, signs of corrosion,
silicone, etc.).
If the connector(s) is faulty and if there is a
repair procedure (see Technical Note 6015A,
Repairing electrical wiring, Wiring:
Precautions for repair), repair the connector,
otherwise replace the wiring.Check the diesel filter.
Has the diesel fuel filter reached its full mileage?
Replace the diesel filter (see MR 364 (Mégane II)
or MR 370 (Scénic II), Mechanical, 13A, Fuel
supply, Fuel filter: Removal - Refitting).
Contact the Techline if the customer complaint is
still present.
Contact the Techline if the customer complaint
is still present.
A
YES
NO
YES
Page 186 of 198

13B-186
AFTER REPAIRCarry out a road test, then check with the diagnostic tool.
V4 MR-372-J84-13B000$140.mif
DIESEL INJECTION
Fault finding – Fault finding charts13B
InjectionDDCR
Vdiag No.: 44, 48
ALP 13 Excessive consumption
NOTESOnly consult this customer complaint after a full check with the diagnostic tool.
Check that the fuel tank is correctly filled and that the fuel is correct by running TEST 13 Diesel fuel conformity
check.
Check the levels of engine oil and coolant.
Is the fuel temperature sensor leaking?Replace the fuel temperature sensor
(see MR 364 (Mégane II) or MR 370
(Scénic II), Mechanical, 13B, Diesel
injection, Rail pressure sensor:
Removal - Refitting).
Check the low pressure circuit by running TEST 1 Low pressure circuit check.
Check the injectors by running TEST 3 Injector check.
Visually check that there are no leaks on the high pressure circuit by running TEST 7 High pressure circuit
sealing check.
Check the air inlet circuit by running TEST 5 Inlet circuit check.
YES
NO
A
DDCR_V44_ALP13/DDCR_V48_ALP13