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.
