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V13
13B
DIESEL INJECTION
Fault finding – Fault Finding Chart
ALP 1 No dialogue with engine management computer
Try to establish dialogue with a computer on another vehicle to check that the diagnostic tool is not faulty.
Check the battery voltage and carry out the operations necessary to obtain the correct voltage
(9.5V
If the tool is not at fault, and dialogue cannot be established with any other computer on the same vehicle, the
cause could be a faulty computer interfering on the multiplex network.
disconnect the engine management computer.
try to establish dialogue with another computer.
if the fault is still present, reconnect the computer and proceed by elimination by successively disconnecting all
the following computers (according to wiring diagram and equipment): air conditioning, airbag, abs and esp, uch,
instrument panel, central communication unit, proximity sensor.
try to establish a dialogue between each disconnection:
if, after a disconnection, you manage to establish dialogue, perform the fault finding procedure for the relevant
computer.
Carry out a fault finding procedure on the multiplex network using the diagnostic tool.
Check for the injection fuses on the protection and switching unit and/or in the engine fuse box and check their
condition.
Check the connection of the computer connectors and the condition of its connections.
Check the injection computer earths (quality, oxidation, tightness of earth bolts on the battery terminal).
Check that the supply to the computer is correct:
Earth on connections NT (Laguna II) or N (Scénic II and Mégane II) of component 120.
+ after ignition feed on connection AP29 (Laguna II) or AP15 (Scénic II and Mégane II) of component 120.
Check that the power supply to the diagnostic socket is correct:
– + before ignition feed on connection BP32 (Scénic II and Mégane II) or BCP4 (Laguna II) of component
225.
– + after ignition feed on connection AP43 (Scénic II and Mégane II) or AP10 (Laguna II) of component
225.
– Earth on connections MAN and NAM (Scénic II and Mégane II) or MA and NAP (Laguna II) of component
225.
If dialogue has still not been established after these checks, contact the techline.
AFTER REPAIRCarry out a road test followed by a complete check with the diagnostic tool.
EDC16_V50_ALP1/EDC16_V58_ALP1/EDC16_V5C_ALP1/EDC16_V18_ALP1/EDC16_V1C_ALP1/EDC16_V20_ALP1 EDC16
Program No.: C1
Vdiag no.: 18, 1C, 20,
50, 58, 5C
MR-372-J84-13B200$828.mif
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13B-346
MR-372-J84-13B200$900.mif
V13
DIESEL INJECTION
Fault finding – Tests
EDC16
Program No.: C1
Vdiag no.: 18, 1C, 20,
50, 58, 5C
13B
* OCR: Opening Cyclic Ratio
TEST 5 Air flowmeter
Impurities in the grilles:
Visual inspection: remove the flowmeter. There should be no foreign bodies on the grilles (see diagram 110734).
Do not clean the grilles using compressed air or any other procedure: this damages the sensors and
creates variations from the values displayed on the CLIP tool.
Check the sealing of the air circuit upstream of the air flowmeter:
disconnected or pierced pipes and air filter unit, seals present.
Replace the air flowmeter if necessary and clean upstream of this, if necessary.
Damage to electrical components:
Visual inspection:
– remove the flowmeter, the components should not be broken (see diagram no. 110736).
Replace the air flowmeter if necessary.
Oxidation of the electrical components:
Visual inspection:
– remove the air flowmeter, there must not be any green deposits on the electrical components.
Replace the air flowmeter if necessary.
Clogging of the air flowmeter:
Te s t :
– Check the values for conformity:
* During the first 5 seconds after starting:
– Coolant temperature: 80°C.
– Engine speed: at idle speed (750 rpm < PR055 < 850 rpm).
– Air flow measurement: 37 kg/h < PR132 < 57 kg/h.
– EGR valve OCR*: between - 10% and 0%.
* After the starting phase:
– Coolant temperature: 80°C,
– Engine speed: at idle speed (750 rpm < PR055 < 850 rpm).
– Air flow measurement: 25 kg/h < PR132 < 35 kg/h.
– EGR valve OCR*: between 10% and 40%.
– Refer to the interpretation of DF056 Air flow sensor circuit 2.DEF, for the air flowmeter checks.
Replace the air flowmeter if necessary.
EDC16_V50_TEST5/EDC16_V58_TEST5/EDC16_V5C_TEST5/EDC16_V18_TEST5/EDC16_V1C_TEST5/EDC16_V20_TEST5
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13B-352
MR-372-J84-13B200$936.mif
V13
DIESEL INJECTION
Fault finding – Tests
EDC16
Program No: C1
Vdiag No: 18, 1C, 20,
50, 58, 5C
13B
TEST 9
CONTINUED 2
Section B: Confirmation of flow correction fault finding for each injector (individual correction):
Clear the faults and perform a test with the engine idling for at least 5 minutes and fuel temperature > 50°C.
Check that no fault appears on the CLIP diagnostic tool and that the corrective values do not reach ±5mg/
stroke to confirm the repair.
If the customer complaint is still present and the fuel flow correction values are between
-5 mg/stroke and + 5mg/stroke, apply Part A Fuel regulation balance check for each injector (individual)
of this test (Case no.4).
If one or more cylinders has an injector flow correction value in excess of ± 5 mg/stroke, apply Part A Fuel
regulation balance check for each injector (individual) of this test, as one or more injectors may be defective.
Part C: Measuring fuel return flow
1 – Fitting the tool:
This section is only to be carried out if PR063 "Fuel temperature" is higher than 50°C (see step 2 of
section C for this test).
Remove the engine undertray
Disconnect the entire fuel return pipe in accordance with the following procedure (do not remove the clips):
– press the clip,
– pull vertically on the end piece (see arrow in the diagram below) of the fuel return pipe.
IMPORTANT
The end piece is fragile. Be careful not to break it by pulling it too hard. Replace all removed clips
Page 353 of 365
13B-353
MR-372-J84-13B200$936.mif
V13
DIESEL INJECTION
Fault finding – Tests
EDC16
Program No: C1
Vdiag No: 18, 1C, 20,
50, 58, 5C
13B
TEST 9
CONTINUED 3
Fit the blanking plugs (B), from the kit (part number 77 01 208 229), on the end pieces of the fuel return pipe.
If Mot. 1760 is not fitted on the injectors immediately, place blanking plugs (A) on the injector fuel return openings.
On the pipes of Mot.1760 (see illustration 113195 above), remove the clips and the plugs from the end pieces
(on the right in the diagram) and leave the plugs (on the left in the diagram) in place.