cooling RENAULT SCENIC 2011 J95 / 3.G Engine And Peripherals Workshop Manual

13B-12V4 MR-372-J84-13B000$020.mif
DIESEL INJECTION
Fault finding – System operation13B
DDCR INJECTION
Vdiag No.: 44, 48
Functions included
Air conditioning management assistance
For vehicles with air conditioning, the DDCR system can switch off the air conditioning under certain engine
operating conditions:
– 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 transition phases (e.g. under heavy acceleration when overtaking, anti-stalling and moving off strategies).
These conditions are only taken into account when they do not occur repeatedly, in order to prevent system
instabilities (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:
– managing demand for cold air according to the passenger compartment commands and the pressure value,
– determining the power absorbed by the compressor from the pressure,
– determining the fan unit commands according to vehicle speed and pressure.
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.
Thermal regulation of the passenger compartment heating circuit
In a direct injection engine, fuel is injected directly into the combustion chamber. This leads to heat being lost
through the upper part of the engine and consequently, the cylinder head cooling circuit is smaller in size.
The effect of this is that the temperature of the coolant flowing through this circuit rises more slowly. However, this
coolant is also used by the passenger compartment heating system. In very cold conditions, it is therefore difficult to
achieve a comfortable passenger compartment temperature quickly.
To limit the time taken to warm up the system, air heating resistors, called RCHs, are fitted into the passenger
compartment heating circuit. The UCH decides whether the RCH are required, the UPC physically actuates
the RCH, and the injection computer determines whether to limit the power supplied to the RCH depending on
alternator charge, and also whether to disable them according to engine speed, load and vehicle speed. NOTE:
Fan unit actuation requests can be made by the injection computer, but these are sent on the CAN. These requests
depend on the air conditioning but also on the coolant temperature and vehicle speed.

13B-97V4 MR-372-J84-13B000$070.mif
DIESEL INJECTION
Fault finding – Conformity check13B
DDCR INJECTION
Vdiag No.: 44, 48
ENGINE COOLING SUB FUNCTION:
NOTESOnly check conformity after a full check with the diagnostic tool.
The values shown in this conformity check are given as examples.
Application conditions: Engine off, ignition on.
FunctionParameter or Status
Check or actionDisplay and notes Fault finding
Coolant
temperaturePR064: Coolant
temperature.
Warm: 90 °CIndicates the coolant
temperature in °C.
Default value: 80°CIn the event of a fault, consult
the interpretation of
parameter PR064 Coolant
temperature.

13B-117V4 MR-372-J84-13B000$070.mif
DIESEL INJECTION
Fault finding – Conformity check13B
DDCR INJECTION
Vdiag No.: 44, 48
ENGINE COOLING SUB FUNCTION:
NOTESOnly check conformity after a full check with the diagnostic tool.
The values shown in this conformity check are given as examples.
Application conditions: Engine off, ignition on.
FunctionParameter or Status
Check or actionDisplay and notes Fault finding
Coolant
temperaturePR064: Coolant
temperature.
Warm: 90°CIndicates the coolant
temperature in °C.
Default value: 80°CIn the event of a fault,
consult the interpretation
of parameter PR064
Coolant temperature.