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.
