Page 497 of 510

13B-497V12 MR-372-J84-13B300$180.mif
DIESEL INJECTION
Fault finding – Test13B
TEST3 Low pressure circuit check
Check the fuel filter:
– Conformity of the fuel filter (correct part number and RENAULT filter).
– Positioning and degree of clogging of the filter cartridge.
– Positioning and condition of the seals.
– If there is metal swarf in the filter:
Replace the fuel filter, bleed the circuit and continue the fault finding procedure.
Supplying the injection system with fuel from an additional tank.
This operation aims to detect possible faults in the low pressure supply system of a vehicle by replacing it entirely
with an additional tank.
Mode:
– Disconnect the diesel fuel supply pipe at the fuel filter inlet and block it with a plug.
– Connect a pipe to the fuel filter inlet and insert the other end in a clean container with a capacity of approximately
5 litres.
– Disconnect the diesel fuel return pipe at the diesel temperature sensor (pump return and injector return join), and
block it using a plug.
– Connect a transparent pipe to the union of the diesel fuel temperature sensor, and insert the other end in the
container.
– Fill the container with clean diesel fuel.
– Start the engine and let the system drain itself of its air (there must not be any air bubbles in the return pipe).
Is the customer complaint still present?If the low pressure circuit is in order, reconnect the
various low pressure circuit pipes, and repeat the
fault finding chart procedure or the procedure for
the fault that referred you to this test.
Are the low pressure circuit connections in order
and in good condition?Carry out the necessary repairs.
YES
NO
NO
A
YES
EDC16CP33_V18_TEST3 / EDC16CP33_V1C_TEST3 / EDC16CP33_V54_TEST3 / EDC16CP33_V20_TEST3 / EDC16CP33_V58_TEST3 /
EDC16CP33_V5C_TEST3 / EDC16CP33_V24_TEST3 / EDC16CP33_V04_TEST3 / EDC16CP33_V08_TEST3 / EDC16CP33_V44_TEST3 /
EDC16CP33_V4C_TEST3 / EDC16CP33_V34_TEST3 / EDC16CP33_V38_TEST3 / EDC16CP33_V74_TEST3 / EDC16CP33_V28_TEST3 /
EDC16CP33_V62_TEST3 / EDC16CP33_V26_TEST3 / EDC16CP33_V60_TEST3
EDC16CP33
Program No.: C4
Vdiag No.: 04, 08, 18, 1C,
20, 24, 26, 28, 34, 38, 44,
4C, 54, 58, 5C, 60, 62, 74
Page 498 of 510

13B-498V12 MR-372-J84-13B300$180.mif
DIESEL INJECTION
Fault finding – Test13B
TEST3
CONTINUED
Check the condition and operation of the priming bulb. Perform repairs if necessary and continue the test.
Check the condition of all the low pressure diesel pipes from the tank to the injection pump (in particular no pinching
of pipes).
If the fault is still present with a low fuel level, check the consistency of the actual fuel level and that indicated on
the instrument panel.
The transfer pump is supplied via a Venturi pipe located underneath it.
Check that the opening of the venturi (6 mm to 8 mm in diameter) is not blocked by dirt contained in the fuel tank.
Check the priming of the low pressure diesel circuit.
Check that the fuel tank is correctly filled and that the fuel is correct (see Test 12 Diesel fuel conformity check).
If the diesel fuel is not correct:
– Replace the fuel (diesel fuel).
– Replace the fuel filter (diesel fuel).
– Bleed the low and high pressure fuel circuit (diesel fuel).
Low pressure circuit correct.
A
YES
EDC16CP33
Program No.: C4
Vdiag No.: 04, 08, 18, 1C,
20, 24, 26, 28, 34, 38, 44,
4C, 54, 58, 5C, 60, 62, 74
Page 502 of 510

13B-502V12 MR-372-J84-13B300$180.mif
DIESEL INJECTION
Fault finding – Test13B
TEST6 Fuel return rail valve check
This test consists of creating a vacuum downstream of the anti-return valve of the injector return rail and checking
whether fuel is drawn in by the valve.
Fitting:
Remove the rail protector.
Disconnect the union of the return rail on injector 4 (on the gearbox side).
Disconnect the union downstream of the anti-return valve.
Connect the 8 mm quick-release coupling.
Connect a transparent hose (resistant to diesel, length 60 cm and internal diameter 8 mm).
Connect a manual vacuum pump.
Gradually apply a vacuum up to 0.5 bar.
If more than a cm of diesel is quickly drawn into the hose, the valve is leaking. Stop the vacuum immediately.
Replace the diesel injector fuel return rail and its overpressure valve (see MR364 (Mégane II ph2), MR370 (Scénic
II ph2), MR 395 (Laguna II ph2), MR 402 (Vel-Satis ph2), MR405 (Espace IV ph2) Mechanical, 13B, Diesel
injection, Diesel injector fuel return rail: Removal - Refitting).
Otherwise, maintain the vacuum for 1 minute.
If less than a cm of diesel is drawn into the hose, the valve of the rail is not leaking.
End of test.
EDC16CP33
Program No.: C4
Vdiag No.: 04, 08, 18, 1C,
20, 24, 26, 28, 34, 38, 44,
4C, 54, 58, 5C, 60, 62, 74
EDC16CP33_V18_TEST6 / EDC16CP33_V1C_TEST6 / EDC16CP33_V54_TEST6 / EDC16CP33_V20_TEST6 / EDC16CP33_V58_TEST6 /
EDC16CP33_V5C_TEST6 / EDC16CP33_V24_TEST6 / EDC16CP33_V04_TEST6 / EDC16CP33_V08_TEST6 / EDC16CP33_V44_TEST6 /
EDC16CP33_V4C_TEST6 / EDC16CP33_V34_TEST6 / EDC16CP33_V38_TEST6 / EDC16CP33_V74_TEST6 / EDC16CP33_V28_TEST6 /
EDC16CP33_V62_TEST6 / EDC16CP33_V26_TEST6 / EDC16CP33_V60_TEST6
Page 504 of 510

13B-504V12 MR-372-J84-13B300$180.mif
DIESEL INJECTION
Fault finding – Test13B
TEST10
CONTINUED 1
2. If at least one of these values is X < - 5 mg/stroke
– Check the valve clearance.
– Check the level and condition of the engine oil.
– Remove the injector with the largest adjustment.
– If there is contamination via the diesel, check the condition of the cylinder concerned (cylinder, piston, valves).
– Replace the injector* concerned.
– See paragraph Part C, for confirmation of the fault finding.
3. If at least one of these values does not stabilise (20 seconds after starting):
– Check the low pressure circuit using Test 3 Low pressure circuit test.
– Check the fuel is correct by carrying out Test 12 Diesel fuel conformity check.
See paragraph Part C of Test 10, for confirmation of the fault finding.
After replacing an injector, follow the injector code programming procedure (see Replacement of components),
run SC036 Reinitialise programming and select the number of the injector replaced.
IMPORTANT:
When removing / refitting injectors, follow the cleanliness and safety instructions (see MR 395 (Laguna II ph2),
402 (Vel Satis), 405 (Espace IV Ph2), 364 (Megane II ph2), 370 (Scenic II ph2) Mechanical, 13B, Diesel
injection, Diesel injectors: Removal - Refitting).
EDC16CP33
Program No.: C4
Vdiag No.: 04, 08, 18, 1C,
20, 24, 26, 28, 34, 38, 44,
4C, 54, 58, 5C, 60, 62, 74
Page 508 of 510

13B-508V12 MR-372-J84-13B300$180.mif
DIESEL INJECTION
Fault finding – Test13B
TEST12 Diesel fuel conformity check
WARNING
During this operation, it is essential to:
– refrain from smoking or bringing incandescent objects close to the work area,
– guard against petrol splashes caused by the residual pressure in the pipes,
– wear safety goggles with side guards,
– wear leaktight gloves (Nitrile type).
IMPORTANT
– To avoid any corrosion or damage, protect the areas on which fuel is likely to run.
– To prevent impurities from entering the circuit, place protective plugs on all fuel circuit components
exposed to the open air.
Preparations:
Weigh an empty 1300 ml plastic cup (part no. 77 11 171 413) with its cover (part no. 77 11 171 416) using
electronic scales such as those used in body paint workshops (example: PANDA part no. 77 11 224 995). Record
the weight of the empty plastic cup.
This type of plastic cup is used to prepare paint.
Remove 1 litre of fuel from the diesel fuel filter outlet (see MR395 (Laguna II ph2) or MR402 (Vel Satis ph2)
or MR405 (Espace IV ph2) or MR364 (Mégane II ph2) or MR370 (Scénic II ph2), Mechanical, 19C, Tank, Fuel
tank: Draining), using a pneumatic transfer pump (part no. 634-200) and place it in the 1300 ml plastic cup.
Cover the plastic cup with its cover and let it settle for approximately2 minutes.
Is the fuel cloudy or does it
separate into two parts?Presence of water in diesel fuel, the fuel is not compliant.
Drain the fuel circuit, including the tank (see MR395 (Laguna II
ph2) or MR402 (Vel Satis ph2) or MR405 (Espace IV ph2) or
MR364 (Mégane II ph2) or MR370 (Scénic II ph2), Mechanical,
19C, Tank, Fuel tank: Draining).
YES
A
NO
EDC16CP33_V18_TEST12 / EDC16CP33_V1C_TEST12 / EDC16CP33_V54_TEST12 / EDC16CP33_V20_TEST12 /
EDC16CP33_V58_TEST12 / EDC16CP33_V5C_TEST12 / EDC16CP33_V24_TEST12 / EDC16CP33_V04_TEST12 /
EDC16CP33_V08_TEST12 / EDC16CP33_V44_TEST12 / EDC16CP33_V4C_TEST12 / EDC16CP33_V34_TEST12 /
EDC16CP33_V38_TEST12 / EDC16CP33_V74_TEST12 / EDC16CP33_V28_TEST12 / EDC16CP33_V62_TEST12/
EDC16CP33_V26_TEST12 / EDC16CP33_V60_TEST12
EDC16CP33
Program No.: C4
Vdiag No.: 04, 08, 18, 1C,
20, 24, 26, 28, 34, 38, 44,
4C, 54, 58, 5C, 60, 62, 74