DIESEL INJECTION
Fault finding – Introduction13B
13B - 3V3 MR-372-J84-13B250$045.mif
EDC16
PROGRAM No: C1
Vdiag No.: 51
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 data that does not produce a fault on the diagnostic tool because the
data is 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 complaints.
A synopsis of the general procedure to follow is provided on the following page in
the form of a flow chart
DIESEL INJECTION
Fault finding – Introduction13B
13B - 4V3 MR-372-J84-13B250$045.mif
EDC16
PROGRAM No: C1
Vdiag No.: 51
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 faults
no
Faults
present
yes
Deal with present faults
Deal with stored faults
no
The cause is
still presentFault
solved
yes
Refer to ALP No. 1
Conformity check
no
The cause is
still presentFault
solved
yes
Use fault finding charts
(ALPs)
no
The cause is
still presentFault
solved
yes
Contact the Techline with the
completed fault finding log
* Check the battery charge, the condition of the fuses and
the level in the tank.
DIESEL INJECTION
Fault finding – Cleanliness guidelines13B
13B - 7V3 MR-372-J84-13B250$033.mif
EDC16
PROGRAM NO.: C1
Vdiag No.: 51DIESEL INJECTION
Fault finding – Cleanliness guidelines
I - RISKS ASSOCIATED WITH CONTAMINATION
The high pressure direct injection system is highly sensitive to contamination. 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 have entered the system during dismantling.
The cleanliness principle must be applied from the filter to the injectors.
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.
II - NOTES TO BE FOLLOWED BEFORE ANY OPERATION
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.IMPORTANT
Cleaning the engine using a high pressure washer is prohibited because of the risk of damaging connections. In
addition, moisture may collect in the connectors and create electrical connection faults.
IMPORTANT
Before any work is carried out on the high pressure injection system, protect:
–the accessories and timing belts,
–the electrical accessories, (starter, alternator, electric power-assisted steering pump),
–the flywheel surface, to prevent any diesel from running onto the clutch friction plate.
MR-372-J84-13B250$033.mif
DIESEL INJECTION
Fault finding – Cleanliness guidelines13B
13B - 8V3 MR-372-J84-13B250$033.mif
EDC16
PROGRAM NO.: C1
Vdiag No.: 51
Check that you have hermetically resealable plastic bags for storing removed parts. Parts stored in this way will be
less susceptible to the risk of contamination. The bags are to be used once only, and discarded after use.
Use lint-free cleaning cloths (cloth part number 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, the parts, unions and injection system zones). 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.
III - 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. The plugs must not be reused under any circumstances.
Seal the pouch shut, even if it has to be opened shortly afterwards. Ambient air carries contamination.
All components removed from the injection system must be stored in a hermetically sealed plastic bag once they
have been plugged.
Using a brush, cleaning agent, air gun, sponge or normal cloth is strictly prohibited once the circuit has been opened.
These items could allow contamination to enter the system.
A new component replacing an old one must not be removed from its packaging until it is to be fitted to the vehicle.
DIESEL INJECTION
Fault finding – System operation13B
13B - 10V3 MR-372-J84-13B250$135.mif
EDC16
PROGRAM No: C1
Vdiag No.: 51
a) The computer:
Determines the value of injection pressure necessary for the engine to operate correctly and then controls the
pressure regulator.
Checks that the pressure value is correct by analysing the value transmitted by the pressure sensor located on the rail.
Determines the injection duration necessary for supplying the correct quantity of diesel and the moment when
injection is required; controls each injector electrically and individually after determining these 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 (EGR),
–fuel supply check (advance, flow and rail pressure),
–the CMV control via the Protection and Switching Unit (centralised coolant temperature management function),
–the air conditioning (cold loop function),
–the cruise control/speed limiter function,
–pre-post heating control,
–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 (MPROP) 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.
DIESEL INJECTION
Fault finding – System operation13B
13B - 12V3 MR-372-J84-13B250$135.mif
EDC16
PROGRAM No: C1
Vdiag No.: 51
c) Hosted functions:
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 transitory phases (such as demands for high acceleration when overtaking, anti-stall and start-up) These
conditions are only taken into account when they do not occur repeatedly, to prevent instability in the system
(erratic deactivations),
–when certain faults appear.
Cold loop air conditioning management:
The air conditioning is the cold loop type and its management 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 GMV, from the UPC, according to the vehicle speed, the refrigerant pressure and the
engine coolant temperature.
The driver requests the air conditioning to be switched on by means of the ventilation selector coupled to a switch.
The cold air request is authorised or denied depending on the pressure measured. If this pressure is outside the
operating limits, the cold loop program is not activated.
Management of the damper valve:
The damper valve currently has three functions:
–the valve closes in order to block the passage of air towards the cylinders to shut off the engine. The aim of this is
to stop the engine as quickly as possible and to reduce instabilities as the engine is switched off.
–"valving" function depending on the engine operation: the damper valve closes by a few % to create a ''venturi''
effect at the EGR valve passage section.
The aim of this is to accelerate the air flow of EGR gases and to reduce the emission of pollutants.
DIESEL INJECTION
Fault finding – System operation13B
13B - 15V3 MR-372-J84-13B250$135.mif
EDC16
PROGRAM No: C1
Vdiag No.: 51
EOBD* management:
The OBD (On Board Diagnostic) system enables the 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 driving cycles and the following parameters will be registered in the computer:
–engine load,
–vehicle speed
–air temperature
–coolant temperature,
–turbocharging pressure,
–rail pressure,
–air flow,
–distance travelled in miles by the vehicle since activation of the OBD warning light.
It allows the driver to know whether the 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:
–DF001 Coolant temperature sensor circuit.
–DF003 Atmospheric pressure sensor circuit.
–DF011 Sensor feed voltage no. 1.
–DF012 Sensor feed voltage no. 2.
–DF013 Sensor feed voltage no. 3.
–DF038 Computer in 6.DEF EEPROM fault.
–DF040 Cylinder 1 injector circuit in CO Open circuit.
–DF041 Cylinder 2 injector circuit in CO Open circuit.
–DF042 Cylinder 3 injector circuit in CO Open circuit.
–DF043 Cylinder 4 injector circuit in CO Open circuit.
–DF054 Turbocharging solenoid valve control circuit in CC.0 Short circuit to earth.
–DF056 Air flow sensor circuit.
–DF209 EGR valve position sensor circuit.
–DF621 EGR valve jammed open.
Some repair operations require programming to ensure that certain engine components function correctly.
Follow the programming procedures (see Replacement of components), if replacing the exhaust gas
recirculation valve or an injector.
*EOBD: Electronic on board diagnostics
DIESEL INJECTION
Fault finding – System operation13B
13B - 16V3 MR-372-J84-13B250$135.mif
EDC16
PROGRAM No: C1
Vdiag No.: 51
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 needs to
go 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.