DIESEL INJECTION
Fault finding – Introduction13B
13B - 6V3 MR-372-J84-13B250$045.mif
EDC16
PROGRAM No: C1
Vdiag No.: 51
5. FAULT FINDING LOG
You will always be asked for this log:
●when requesting technical assistance from Techline,
●for approval requests when replacing parts for which approval is mandatory,
●to be attached to monitored parts for which reimbursement is requested. The log is needed for warranty
reimbursement, and enables better analysis of the parts removed.
6. SAFETY ADVICE
Safety rules must be observed during any work on a component to prevent any damage or injury:
–make sure that the battery is properly charged to avoid damaging the computers with a low load,
–use the appropriate tools.
7. CLEANLINESS ADVICE TO FOLLOW WHEN CARRYING OUT OPERATIONS ON THE HIGH PRESSURE
DIRECT INJECTION SYSTEM
Risks relating to contamination
The system is highly sensitive to contamination. The risks associated with contamination are:
–damage to or destruction of the high pressure injection system and the engine,
–a component seizing or leaking.
All After-Sales operations must be performed under very clean conditions. This means that no impurities (particles a
few microns in size) should be allowed to penetrate the system during dismantling or get into the circuits via the fuel
unions.
The cleanliness guidelines must be applied from the filter through to the injectors.IMPORTANT!IMPORTANT
Any fault on a complex system requires thorough fault finding with the appropriate tools. The
FAULT FINDING LOG, which should be completed during the procedure, enables you to keep
track of the procedure which is carried out. It is an essential document when consulting the
manufacturer.
IT IS THEREFORE COMPULSORY TO COMPLETE A FAULT FINDING LOG
EVERY TIME A FAULT FINDING PROCEDURE IS PERFORMED
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 - 9V3 MR-372-J84-13B250$135.mif
EDC16
PROGRAM No: C1
Vdiag No.: 51DIESEL INJECTION
Fault finding – System operation
System outline
The high pressure injection system is designed to deliver a precise quantity of diesel fuel to the engine at a set
moment.
It is fitted with a 112-track BOSCH EDC16 C3 type computer.
The system is comprised of:
–a priming bulb on the low pressure circuit,
–a diesel filter,
–a high pressure pump with a built-in low pressure pump (transfer pump),
–a high pressure regulator mounted on the pump,
–an injector rail,
–a diesel fuel pressure sensor built into the rail,
–four solenoid injectors,
–a coolant temperature sensor,
–a cylinder reference sensor,
–an engine speed sensor,
–a turbocharger pressure sensor,
–an accelerator pedal potentiometer,
–an EGR solenoid valve,
–an atmospheric pressure sensor integrated into the injection computer,
–an air flow sensor with an air temperature sensor,
–a turbocharging pressure limitation solenoid valve,
–a motorised damper valve.
The common rail direct high pressure injection system works sequentially (based on the petrol engine multipoint
injection).
This injection system reduces operating noise, reduces the volume of pollutant gases and particles and produces
high engine torque at low engine speeds thanks to a pre-injection procedure.
The high pressure pump generates the high pressure and transmits it to the injector rail. The actuator located on the
pump controls the quantity of diesel fuel supplied, according to the requirement determined by the computer. The rail
supplies each injector through a steel pipe.
MR-372-J84-13B250$135.mif
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 - 11V3 MR-372-J84-13B250$135.mif
EDC16
PROGRAM No: C1
Vdiag No.: 51
b) Multiplex connection between the different vehicle computers.
The electronic system fitted in this vehicle is multiplexed.
This enables dialogue between the various vehicle computers. As a result:
–the activation of the fault warning lights on the instrument panel is performed by the multiplex network, with the
vehicle speed sensor on the gearbox deactivated,
–vehicle faults are displayed by the multiplex network,
–the vehicle speed sensor on the gearbox is not needed.
The vehicle speed signal on the instrument panel is transmitted by the ABS computer via a wire connection, then
sent out on the multiplex network by the instrument panel. The vehicle speed signal is used mainly by the injection
computer and the airbag computer.
Some vehicles have adopted a sensor for detecting water in the diesel fuel, located in the filter. If there is water in the
diesel fuel, the orange "Injection and pre-post heating" warning light will come on.
The system can inject diesel fuel into the engine at a pressure of up to 1600 bar. Before each operation, check that
the injector rail is depressurised and that the fuel temperature is not too high.
You must respect the cleanliness guidelines and safety advice specified in this document for any work on the high
pressure injection system.
Removal of the internal parts of the pump and injectors is prohibited. Only the fuel flow actuator, the diesel fuel
temperature sensor and the venturi can be replaced.
For safety reasons, it is strictly prohibited to undo a high pressure pipe union when the engine is running.
It is not possible to remove the pressure sensor from the fuel rail because this may cause circuit contamination
faults. If the pressure sensor fails, the pressure sensor, the rail and the five high pressure pipes must be replaced.
It is forbidden to remove any injection pump pulley bearing the number 070 575. If the pump needs to be replaced,
replace the pulley.
Supplying + 12 V directly to any component in the system is prohibited.
Ultrasonic decoking and cleaning are prohibited.
Never start the engine unless the battery is connected correctly.
Disconnect the injection computer when carrying out any welding work on the vehicle.WARNING
The engine must not operate with:
–Diesel fuel containing more than 10 % diester,
–petrol, even in tiny quantities.
DIESEL INJECTION
Fault finding – Allocation of computer tracks13B
13B - 17V3 MR-372-J84-13B250$180.mif
EDC16
PROGRAM No: C1
Vdiag No.: 51DIESEL INJECTION
Fault finding – Allocation of computer tracks
1 - black connector A, 32 tracks 1 - black connector A, 32 tracks (continued)
Track Description
A1Not used
A2Cruise control on/off switch
A3Passenger compartment L1 multiplex
line network signal
A4Passenger compartment H1 multiplex
line network signal
B1Air conditioning inhibition control
B2Engine speed signal
B3Not used
B4K line diagnostic socket output
C1Not used
C2Not used
C3Speed limiter on/off switch
C4Clutch contact input
D1Protection and Switching Unit supply
(+ after ignition feed)
D2Cruise control programming control
D3Cruise control programming feedback
signal
D4Fuel flow signal
E1Not used
E2Air conditioning cycle control
E3Not used
E4Normally-closed brake switch input
F1Not used
F2Accelerator potentiometer load 2
supply
F3Accelerator potentiometer load 2 signal
F4Accelerator potentiometer load 2 earth
Track Description
G1Protection and Switching Unit supply
(+ BAT 1 after relay)
G2Accelerator potentiometer load 1
supply
G3Not used
G4Battery earth
H1Battery earth
H2Accelerator potentiometer load 1 signal
H3Accelerator potentiometer load 1 earth
H4Battery earth
MR-372-J84-13B250$180.mif
DIESEL INJECTION
Fault finding – Allocation of computer tracks13B
13B - 18V3 MR-372-J84-13B250$180.mif
EDC16
PROGRAM No: C1
Vdiag No.: 51
2 - brown connector B, 48 tracks 2 - Brown 48-track connector B (continued)
Track Description
A1Camshaft sensor earth (cylinder 1
reference)
A2Not used
A3Not used
A4Fuel rail pressure sensor supply
B1TDC sensor supply signal (engine
speed)
B2Damper valve fault finding
B3Not used
B4Air flow sensor supply
C1TDC sensor earth signal (engine
speed)
C2EGR valve engine supply signal
C3Engine CAN H2 network signal
(automatic gearbox)
C4Fuel rail pressure sensor earth
D1Camshaft sensor signal (cylinder
reference 1)
D2EGR valve engine earth signal
D3Engine CAN L2 network signal
(automatic gearbox)
D4Turbocharger pressure sensor earth
E1Main power supply relay control
E2Air temperature and air flow sensor
earth signal
E3Not used
E4Not used
F1Refrigerant pressure sensor signal
F2Coolant temperature sensor supply
signal
F3Refrigerant pressure sensor supply
F4EGR valve position potentiometer feed
Track Description
G1Air flow sensor supply signal
G2Air temperature signal
G3Fuel rail pressure sensor signal
G4Turbocharging pressure sensor supply
H1Coolant temperature sensor earth
H2Not used
H3Not used
H4Electric coolant pump relay control
J1Not used
J2EGR valve position potentiometer
signal
J3Not used
J4Damper valve solenoid valve control
K1Not used
K2Turbocharger pressure sensor signal
K3Not used
K4Not used
L1Not used
L2Not used
L3Not used
L4Flow sensor earth
M1Not used
M2Protection and Switching Unit supply
(+ BAT 2 after relay)
M3Not used
M4Fuel pressure regulation solenoid valve
control (fuel flow actuator)
DIESEL INJECTION
Fault finding – Replacement of components13B
13B-25V3 MR-372-J84-13B250$225.mif
EDC16
PROGRAM No: C1
Vdiag No.: 51
Summary of available configuration readings
NOTESConfiguration readings are used to check the status of the configurations made.
The configuration readings cannot be changed.
The computer is configured as soon as the one of the vehicle's optional system
components is operated.
In the event of a fault, consult the interpretation of command RZ005 PROGRAMMING.
LC009: Air conditioning
WITH OR WITHOUT
LC065: Water in diesel fuel sensor
WITH OR WITHOUT
LC120: Cruise control
WITH OR WITHOUT
LC121: Speed limiter
WITH OR WITHOUT