13B - 3
DIESEL INJECTION
Fault finding - Introduction13B
V10 MR-372-J84-13B150$047.mif
EDC16 INJECTION
Program No.: C1
Vdiag No.: 44, 48 and 4C
Faults
Faults are declared as either present or stored (depending on whether they appeared in a certain context and have
disappeared since, or whether they remain present but have not been diagnosed within the current context).
The present or stored status of faults should be taken into consideration when the diagnostic tool is switched on
after the + after ignition feed (without any system components being active).
For a present fault, apply the procedure described in the Interpretation of faults section.
For a stored fault, note the faults displayed and apply the instructions in the Notes section.
If the fault is confirmed when the instructions in the Notes section are applied, the fault is present. Deal with the
fault
If the fault is not confirmed, check:
– the electrical lines which correspond to the fault,
– the connectors for these lines (for oxidation, bent pins, etc.),
– the resistance of the component detected as faulty,
– the condition of the wires (melted or split insulation, wear).
Conformity check
The aim of the conformity check is to check statuses and parameters that do not produce a fault display on the
diagnostic tool when they are inconsistent. Therefore, this stage is used to:
– carry out fault finding on faults that do not have a fault display, and which may correspond to a customer
complaint.
– check that the system is operating correctly and that there is no risk of a fault recurring after repairs.
This section gives the fault finding procedures for statuses and parameters and the conditions for checking them.
If a status is not behaving normally or a parameter is outside the permitted tolerance values, consult the
corresponding fault finding page.
Customer complaints - Fault finding chart
If the test with the diagnostic tool is OK but the customer complaint is still present, the fault should be processed by
customer complaint.
A summary of the overall procedure to follow is provided on the following
page in the form of a flow chart.
13B - 4
DIESEL INJECTION
Fault finding - Introduction13B
V10 MR-372-J84-13B150$047.mif
EDC16 INJECTION
Program No.: C1
Vdiag No.: 44, 48 and 4C
4. FAULT FINDING PROCEDURE
Perform a pre-diagnostic on
the system*
Print the system fault finding log
(available on CLIP and in the
Workshop Repair Manual or
Technical Note)
Connect CLIP
no
Dialogue with
computer?
yes
Read the faults
no
Faults
present
yes
Deal with present faults
Deal with stored faults
no
The cause is
still presentFault
solved
yes
* Check the battery charge, the condition of the
fuses and the level in the tank.
See ALP no. 1
Conformity check
no
The cause is
still presentFault
solved
Use Fault Finding Charts
(ALPs)
no
The cause is
still presentFault
solved
Contact the Techline with the
completed fault finding log
13B - 7
DIESEL INJECTION
Fault finding - Introduction13B
V10 MR-372-J84-13B150$047.mif
EDC16 INJECTION
Program No.: C1
Vdiag No.: 44, 48 and 4C
7. CLEANLINESS ADVICE THAT MUST BE OBSERVED WHEN WORKING ON THE HIGH PRESSURE DIRECT
INJECTION SYSTEM
Risks relating to contamination
The direct injection system is very sensitive to pollution. The risks associated with contamination are:
– damage to or destruction of the high pressure injection system,
– components jamming,
– a component leaking.
All After-Sales operations must be performed under very clean conditions.
This means that no impurities (particles a few microns in size) should enter the system during dismantling.
The cleanliness principle must be applied from the filter to the injectors.
WARNING
BEFORE CARRYING OUT ANY WORK ON THE INJECTION SYSTEM, CHECK WITH THE DIAGNOSTIC TOOL:
– that the rail is depressurised,
– that the fuel temperature is not too high.
What are the sources of contamination?
– metal or plastic swarf,
– paint,
– fibres: from cardboard
from brushes,
from paper,
from clothing,
from cloths.
– foreign bodies such as hair,
– ambient air,
–etc.
IMPORTANT
It is not possible to clean the engine using a high pressure washer because of the risk of damaging connections.
In addition, moisture may collect in the connectors and create electrical connection faults.
13B - 8
DIESEL INJECTION
Fault finding - Introduction13B
V10 MR-372-J84-13B150$047.mif
EDC16 INJECTION
Program No.: C1
Vdiag No.: 44, 48 and 4C
Instructions to be followed before any work is carried out on the injection system:
Protect the accessories and timing belts, the electrical accessories (starter, alternator, electric power-assisted
steering pump) and the mating face to prevent diesel fuel spilling onto the clutch friction plate.
Check that you have plugs for the unions to be opened (set of plugs available from the Parts Department). The plugs
are single-use only. After use, they must be discarded (once used they are soiled and cleaning is not sufficient to
make them reusable). Unused plugs must be discarded.
Ensure that you have hermetically resealable plastic bags for storing removed parts. There is less risk of parts
stored in this way being exposed to contamination. These are single-use bags; after use they must be discarded.
Use lint-free cleaning cloths (part no. 77 11 211 707). Using normal cloth or paper is prohibited. They are not lint-free
and could contaminate the fuel circuit. Each cloth should only be used once.
Use fresh cleaning agent for each operation (used cleaning agent is contaminated). Pour it into an uncontaminated
container.
For each operation, use a clean brush in good condition (the brush must not shed its bristles).
Use a brush and cleaning agent to clean the unions to be opened.
Blast compressed air over the cleaned parts (tools, workbench, and the parts, unions and injection system area).
Check that no bristles remain.
Wash your hands before and during the operation if necessary.
When wearing leather protective gloves cover them with latex gloves to prevent contamination.
Instructions to be followed during the operation
As soon as the circuit is open, all openings must be plugged to prevent impurities from entering the system. The
plugs to be used are available from the Parts Department. They must not be reused under any circumstances.
Close the hermetically sealed bag, even if it has to be reopened shortly afterwards. Ambient air carries impurities.
All components removed from the injection system must be stored in a hermetically sealed plastic bag once they
have been plugged.
Using a brush, thinner, air gun, rifle-type brush or normal rag is strictly prohibited once the circuit has been opened.
These items are likely to allow impurities to enter the system.
If a component is being replaced with a new component, do not remove the packaging until it is ready to be fitted to
the vehicle.
13B - 10
DIESEL INJECTION
Fault finding - System operation13B
V10 MR-372-J84-13B150$094.mif
EDC16 INJECTION
Program No.: C1
Vdiag No: 44, 48 and 4C
a) The computer
– Determines the value of injection pressure necessary for the engine to operate correctly and then controls the
pressure regulator.
– It checks that the pressure value is correct by analysing the value transmitted by the pressure sensor located on
the rail.
– It determines the injection timing required to deliver the right quantity of diesel fuel and the moment when injection
should start.
– Controls each injector electrically and individually after determining these two values.
The flow injected into the engine is determined by:
– the duration of injector control,
– the rail pressure (regulated by the computer),
– the injector opening and closing speed,
– the needle stroke (determined by a constant for the type of injector),
– the nominal hydraulic flow of the injector (specific to each injector).
The computer manages:
– idling regulation,
– exhaust gas flow reinjection to the inlet,
– fuel supply check (advance, flow and rail pressure),
– the fan assembly via the Protection and Switching Unit (centralised coolant temperature management
function),
– the air conditioning (cold loop function),
– the cruise control/speed limiter function,
– the pre-postheating control.
– the fault warning lights via the multiplex network.
The high pressure pump is supplied at low pressure by an integrated low-pressure pump (transfer pump).
It supplies the rail, the pressure of which is controlled by the fuel flow actuator for charging, and for discharging by
the injector valves. This compensates for pressure drops.
The fuel flow actuator enables the high pressure pump to supply the exact quantity of diesel fuel required to maintain
the rail pressure. This component minimises the heat generated and improves engine output.
In order to discharge the rail using the injector valves, the valves are controlled by brief electrical pulses which are:
– short enough not to open the injector (passing through the feedback circuit from the injectors),
– long enough to open the valves and discharge the rail.
13B - 12
DIESEL INJECTION
Fault finding - System operation13B
V10 MR-372-J84-13B150$094.mif
EDC16 INJECTION
Program No.: C1
Vdiag No: 44, 48 and 4C
b) Functions included
Air conditioning management assistance
In the case of vehicles with climate control, the EDC16 system has the option of deactivating the air conditioning via
the UCH, under certain conditions of use:
– when requested by the driver,
– when starting the engine,
– if the engine overheats (in order to reduce the power the engine has to supply),
– when the engine speed is kept at a very high level (to protect the compressor),
– during transition phases (e.g. high acceleration demand for overtaking, anti-stalling and moving off). These
conditions are only taken into account if they do not occur repeatedly, so as to prevent system instabilities (erratic
deactivation),
– when certain faults appear.
Cold loop air conditioning management
The air conditioning is cold loop managed, shared between several computers. The injection computer is
responsible for:
– authorising cold requests according to the refrigerant pressure, the engine coolant temperature and the engine
speed,
– calculating the power absorbed by the compressor (from the refrigerant pressure),
– requesting operation of the fan assembly, from the UPC, according to the vehicle speed, the refrigerant pressure
and the engine coolant temperature.
13B - 15
DIESEL INJECTION
Fault finding - System operation13B
V10 MR-372-J84-13B150$094.mif
EDC16 INJECTION
Program No.: C1
Vdiag No: 44, 48 and 4C
d) OBD management
The OBD (On Board Diagnostic) system enables detection of any faults relating to the vehicle emission control
system (OBD EURO IV emission control standards exceeded).
This system should be active for the entire life of the vehicle.
1. Conditions causing an OBD fault
An OBD fault will be detected after 3 operating cycles, and the following parameters will be saved in the calculator:
– engine load,
– vehicle speed,
– air temperature,
– coolant temperature,
– turbocharging pressure,
– rail pressure,
–air flow,
– vehicle mileage.
It allows the driver to know whether their vehicle has a fault directly linked to the emission control system.
2. System faults indicated by the OBD
Only a few faults are indicated by the OBD system:
–DF012 Sensor supply voltage no. 2.
–DF038 Computer.
–DF040 Cylinder 1 injector circuit.
–DF041 Cylinder 2 injector circuit.
–DF042 Cylinder 3 injector circuit.
–DF043 Cylinder 4 injector circuit.
–DF209 EGR valve position sensor circuit.
–DF272 EGR valve control circuit.
–DF621 EGR valve jammed open.
Some repair operations require programming to ensure that certain engine components function correctly.
Follow the programming procedures (described in the component replacement section), if replacing an
exhaust gas recirculation valve or an injector.
13B - 16
DIESEL INJECTION
Fault finding - System operation13B
V10 MR-372-J84-13B150$094.mif
EDC16 INJECTION
Program No.: C1
Vdiag No: 44, 48 and 4C
3. Conditions for clearing an OBD fault
An OBD fault is cleared in several steps.
The fault present in the diagnostic tool is not stored (following repair) until after 3 trips with the vehicle.
The OBD warning light will only light up after these 3 driving cycles.
The warning light coming on does not always mean that there is a fault on the system.
In order that the OBD fault and the display parameters are cleared from the computer, the system goes
through 40 engine heating cycles.
An engine heating cycle is a driving cycle during which:
–the engine coolant temperature reaches at least 71.1 °C,
–the engine coolant temperature varies by 22.2 °C in relation to the engine starting temperature.
If one of these conditions is not fulfilled, the OBD fault will still be present or stored in the injection
computer.