DIESEL INJECTION
Fault finding – Introduction13B
13B - 2V3 MR-372-J84-13B250$045.mif
113B
EDC16
PROGRAM No: C1
Vdiag No.: 51DIESEL INJECTION
Fault finding – Introduction
1. SCOPE OF THIS DOCUMENT
This document presents the fault finding procedure applicable to all computers with the following specifications:
2. PREREQUISITES FOR FAULT FINDING
Documentation type
Fault finding procedures (this manual):
–Assisted fault finding (integrated into the diagnostic tool), Dialogys.
Wiring Diagrams:
–Visu-Schéma (CD-ROM), paper version.
Type of diagnostic tools
–CLIP + CAN sensor
Special tooling required
3. RECAP
Procedure
To run fault finding on the vehicle's computers, switch on the ignition in fault finding mode (forced + after ignition
feed).
–vehicle's card in reader;
–press and hold the Start button (longer than 5 seconds) with start-up conditions not present,
–connect the diagnostic tool and perform the required operations.
To cut off the + after ignition feed, proceed as follows:
–disconnect the diagnostic tool,
–vehicle card in reader,
–press the Start button twice briefly (less than 3 seconds),
–ensure that the + after ignition feed has been cut off by checking that the computer indicator lights on the
instrument panel have gone out. Vehicle(s): MEGANE II, SCENIC II
Engine type and suffix: F9Q 804
Function concerned: DIESEL INJECTIONName of computer: BOSCH EDC16 C3
Program no.: C1
Vdiag No.: 51
Special tooling required
Multimeter
+ Elé. 1590Computer connection bornier
Or Elé. 1681Universal bornier
EDC16_V51_PRELI
MR-372-J84-13B250$045.mif
DIESEL INJECTION
Fault finding – Introduction13B
13B - 5V3 MR-372-J84-13B250$045.mif
EDC16
PROGRAM No: C1
Vdiag No.: 51
FAULT FINDING PROCEDURE (continued)
Wiring check
Fault finding problems
Disconnecting the connectors and/or manipulating the wiring harness may temporarily remove the cause of a fault.
Electrical measurements of voltage, resistance and insulation are generally correct, especially if the fault is not
present when the analysis is made (stored fault).
Visual inspection
Look for damage under the bonnet and in the passenger compartment.
Carefully check the fuses, insulators and wiring harness routing.
Look for signs of oxidation.
Tactile inspection
While manipulating the wiring harness, use the diagnostic tool to note any change in fault status from stored to
present.
Make sure that the connectors are properly locked.
Apply light pressure to the connectors.
Twist the wiring harness.
If there is a change in status, try to locate the source of the fault.
Inspection of each component
Disconnect the connectors and check the appearance of the clips and tabs, as well as the crimping (no crimping on
the insulating section).
Make sure that the clips and tabs are properly locked in the sockets.
Check that no clips or tabs have been dislodged during connection.
Check the clip contact pressure using an appropriate model of tab.
Resistance check
Check the continuity of entire lines, then section by section.
Look for a short circuit to earth, to + 12 V or to another wire.
If a fault is detected, repair or replace the wiring harness.
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 – System operation13B
13B - 14V3 MR-372-J84-13B250$135.mif
EDC16
PROGRAM No: C1
Vdiag No.: 51
Exhaust gas recirculation management
The exhaust gas recirculation system comprises a direct current EGR valve controlled by an H bridge in the
computer. This system has a built-in valve position feedback potentiometer.
The EGR valve is controlled in a closed loop on the change in the air flow measured by the flow sensor.
The potentiometer is used in the fault finding procedure for the EGR valve position.
Warning light management:
Instrument panel display
The computer manages the data display on the instrument panel relating to engine operation. This involves six
functions:
–the pre-postheating warning light,
–the coolant temperature warning light or warning message;
–the fault level 1 warning light (non-critical fault),
–the fault level 2 warning light (emergency stop),
–the OBD warning light (European On Board Diagnostic).
These five functions are represented by 4 or 5 warning lights and/or messages sent by the trip computer.
A 3 second visual inspection is carried out by the injection computer when ignition is switched on (automatic
procedure for test managed by the instrument panel).
Orange Pre-post heating/non-critical fault SERVICE warning light (level 1)
This light is used both as an in-operation indicator light and as a system fault indicator:
–Continuously lit with + after ignition feed:
Indicates preheating of the spark plugs.
–Continuous lighting accompanied by the message CHECK INJECTION or ELECTRONIC FAULT:
Indicates a level 1 fault (implies operation in injection system defect mode).
The driver should carry out repairs as soon as possible.
Temperature warning light/red EMERGENCY STOP (level 2)
This indicator light is used both as an in-operation indicator light and as a system fault warning light. Lights up for
3 seconds when the ignition is switched on (automatic test procedure managed by the instrument panel):
–Continuously lit or alternately lit with ENGINE OVERHEATING message:
Indicates engine overheating (the driver is free to choose whether or not to stop the vehicle).
–Continuously lit with the FAULTY INJECTION message:
Indicates a level 2 fault (In this case, the injection is automatically cut after a few seconds).
The driver should carry out repairs as soon as possible.
ORANGE OBD excess pollution warning light
An engine symbol accompanied by the message CHECK EMISSION CONTROL.
This warning light comes on if the system has one or more OBD faults.
This warning light is used to warn the driver of injection faults leading to excessive pollution or that the EOBD* system
has been deactivated.
The injection computer requests activation of the OBD warning light for a present fault only after three successive
driving cycles.
A 3 second visual inspection is carried out by the injection computer when ignition is switched on (automatic
procedure for test managed by the instrument panel).
*EOBD: Electronic on board diagnostics.
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.
DIESEL INJECTION
Fault finding – Replacement of components13B
13B-20V3 MR-372-J84-13B250$225.mif
EDC16
PROGRAM No: C1
Vdiag No.: 51DIESEL INJECTION
Fault finding – Replacement of components
COMPUTER REPLACEMENT OR REPROGRAMMING
Operations to be carried out before reprogramming the injection computer:
Before reprogramming the injection computer, move the main CC/SL switch to the rest position. The information
about the cruise control or the speed limiter displayed on the instrument panel disappears.
Otherwise, if the main switch remains in the cruise control or speed limiter position during and after reprogramming,
the Cruise control/Speed limiter function will not be operational.
The procedure for resetting the function is as follows:
–Vehicle ignition on.
–Move the cruise control/speed limiter switch to the rest position (the computer detects the rest position at that
moment).
–Move the cruise control/speed limiter switch to the Cruise control position to activate the Cruise control function.
–Move the cruise control/speed limiter switch to the Speed limiter position to activate the Speed limiter function.
Two operations must be performed when replacing or reprogramming the computer:
SC003 Save computer data and SC001 Enter saved data.
–Use SC003 before the computer is replaced or reprogrammed. This enables certain data to be saved in the
diagnostic tool so that the new computer* can be reconfigured like the old one. The saved data are: injector
codes, EGR programming, vehicle options.
–Run SC001 after the computer is replaced or reprogrammed. It enables you to rewrite the data (saved by
command SC003) to the new computer*.
If you cannot establish dialogue with the computer being replaced: you will not be able to save anything. After
replacing the computer, enter the IMA code of each injector manually, reading the code on each injector (see
INJECTOR REPLACEMENT).
Exhaust gas recirculation valve data is programmed automatically the 1
st time the new computer is switched on*.
* new computer or reprogrammed computer. IMPORTANT
–Switch on the diagnostic tool (mains or cigarette lighter supply).
–Connect a battery charger.
–Switch off all electrical consumers (lights, interior lights, air conditioning, radio/CD, etc.).
–Wait for the engine to cool (engine coolant temperature < 60˚ and air temperature < 50˚).
–The GMV are activated automatically when the computer is being reprogrammed.