2011 RENAULT SCENIC coolant level

13B-8V4 MR-372-J84-13B000$020.mif
13B
DDCR INJECTION
Vdiag No.: 44, 48
System outline
The DDCR injection system used on the K9 engine is an electronically managed high pressure injection system.
The fuel is compressed by a high pressure pump then stored in a rail that feeds the injectors. Injection occurs when
a current pulse is applied to the injector holders. The injected flow is proportional to the rail pressure and to
the applied pulse length, and the start of injection is phased with the start of the pulse.
The circuit comprises two subsystems, which are distinguished by the fuel pressure level.
– The low pressure system includes the tank, diesel fuel filter, transfer pump and injector holder return pipes.
– The high pressure circuit contains the high pressure pump, the rail, the injector holders and the high pressure tubes.
Finally, there are a certain number of sensors and regulating actuators for controlling and monitoring the entire
system.
Functions provided
Function: Fuel supply management (timing, flow and pressure).
Quantity of fuel injected and injection timing adjustment
The injection checking parameters are the quantities to be injected and their respective timing. These are calculated
by the computer using signals from the following sensors:
• Engine speed (Crankshaft + Cam for synchronisation)
• Accelerator pedal
• Turbocharging pressure and air temperature (Turbocharger pressure)
• Coolant temperature
• Air temperature
• Air load (Flow and Pressure)
• Rail pressure
• Flowmeter
• Turbocharging solenoid valve
The quantities to be injected and their respective timing are converted into:
• a reference tooth
• the time between this tooth and the start of the pulse
• the time for which the supply to the injector holder is on
An electrical current (pulse) is sent to each injector holder according to previously calculated data. The system
makes one or two injections (1 pilot injection, 1 main injection). The general principle is to calculate an overall
injected flow which will then be divided into a main injection flow and a pilot injection flow, to help the combustion
process work properly and to reduce pollutant emissions.
An accelerometer is used to monitor some of the fuel injection deviation. This has several roles:
• Protecting the engine by detecting injection leaks (disabled on the basic vehicle).
• Checking the pilot quantity by measuring deviation and dispersion
• By changing both the duration and timing of the injection, the quantity of fuel injected and the mixture ignition timing
can be adjusted.
DIESEL INJECTION
Fault finding – System operation

13B-9V4 MR-372-J84-13B000$020.mif
DIESEL INJECTION
Fault finding – System operation13B
DDCR INJECTION
Vdiag No.: 44, 48
Rail pressure check
The quality of combustion is influenced by the size of the atomised droplets in the cylinder. In the combustion
chamber, smaller fuel droplets will have time to burn fully, and will not produce smoke or unburned particles. To
meet the pollution requirements, the droplet size, and therefore the size of the injection holes, must be reduced.
With smaller holes, less fuel will be able to be introduced at a given pressure, which limits the power. To handle this
drawback, the injected fuel flow has to be increased, which means a pressure increase (and more apertures on the
injector nozzles). For the DDCR injection system, the pressure reaches 1400 bar in the rail, and must be constantly
regulated. The measuring circuit consists of an active pressure sensor on the rail connected to an analogue port on
the computer.
The High Pressure pump is supplied at low pressure (5bar) by a built-in transfer pump. This pump supplies the rail.
The rail filling pressure is controlled by the filling valve (IMV) and the discharge pressure is controlled by the injector
valves. This compensates for pressure drops. The filling actuator enables the high pressure pump to supply just
the exact quantity of diesel fuel required to maintain the rail pressure. This mechanism minimises the heat
generated and improves engine output.
In order to discharge the rail using the injector valves, the valves are actuated by short electrical pulses which are:
– short enough not to open the injector (and pass through the return circuit from the injectors),
– long enough to open the valves and discharge the rail.
The fuel surplus is sent back to the fuel filter or the tank, according to its flow. If there is no IMV control, the rail
pressure is limited by a discharge valve fitted on the pump.
Idling speed regulation
The computer handles the calculation of idling speed. This has to take account of the instantaneous power level to
be supplied, according to the following factors:
– Engine coolant temperature
– Gear engaged
– Battery charging
– Electrical consumers (Heating elements, Air conditioning, Fan assembly, Heated windscreen, etc.) active or
inactive
Individual injector correction (C2I)
The DDCR system injectors must be calibrated with corrective values to adjust their flow precisely. Each injector is
calibrated for different pressures on a test bench, and its specifications are shown on a label attached to the body of
the injector holders. These individual correction values are then written to the computer EEPROM, which can then
actuate the injectors by taking into account their manufacturing dispersion.

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-13V4 MR-372-J84-13B000$020.mif
DIESEL INJECTION
Fault finding – System operation13B
DDCR INJECTION
Vdiag No.: 44, 48
Cruise control/speed limiter management:
When activated, the cruise control function maintains the vehicle at a preselected speed, regardless of the driving
conditions encountered. Using the control buttons, the driver can increase or decrease the vehicle speed.
The cruise control function can be deactivated either by using the control buttons or by switching off the cruise
control function selection switch, or when system events are detected such as depressing the brake or clutch
pedals, or when system errors are detected such as an inconsistent vehicle speed or excessive vehicle
deceleration. The cruise control function can also be temporarily suspended when the driver wants to resume
control of the vehicle and exceed the selected cruising speed by depressing the accelerator pedal which then
exceeds the selected fuel flow. The cruising speed is resumed when the driver releases the accelerator pedal.
The cruise control function can be reactivated and the last cruising speed can be resumed after deactivating
the function for whatever reason until the vehicle ignition is switched off (i.e. for as long as computer supply not cut
off). The vehicle will then attempt to return to the cruising speed using a controlled vehicle acceleration rate.
When switched on (using the selection switch), the vehicle speed limiter function limits the vehicle speed to a preset
value. The driver controls the vehicle in the normal way using the accelerator pedal until the limit speed is reached.
If an attempt is made to exceed this speed, the system will ignore the pedal request and will control the vehicle
speed as the cruise control function would do, provided that the driver continues to press the accelerator pedal.
As with the cruise control function, the set speed can be altered by adjusting the control buttons, with single touches
or holding down.
For safety reasons, the cruising speed can be exceeded by depressing the accelerator pedal beyond the pedal
position limiting value. Vehicle speed is then controlled using the accelerator pedal until the vehicle speed is
decreased to below the cruising speed, when the limiter function is activated again.
The driver has the following controls for the cruise control/speed limiter function:
– accelerator pedal,
– brake pedal,
– clutch pedal,
– function selector switch, used to select cruise control or speed limiter operating mode.
Instrument panel display
The computer displays certain information on the instrument panel relating to engine operation. This concerns 5
functions: the MIL (Malfunction Indicator Lamp) of the EOBD (European On Board Diagnostic), pre-postheating,
the coolant temperature, and engine faults: Level 1 (non-critical fault) and Level 2 (emergency stop). These five
functions are represented by 3 warning lights or messages displayed by the on-board computer.
Pre-postheating warning light
This light is used both as an in-operation indicator light and as a system fault indicator:
– permanently lit during + after ignition feed: indicates preheating of the heater plugs.
After preheating and an automatic timed 3 second off period, the warning light will come on if a Level 1 fault occurs
(leading to reduced operation and reduced safety levels. The driver should have repairs carried out as soon as
possible.)

13B-167
AFTER REPAIRCarry out a road test, then check with the diagnostic tool.
V4 MR-372-J84-13B000$140.mif
DIESEL INJECTION
Fault finding – Fault finding charts13B
InjectionDDCR
Vdiag No.: 44, 48
ALP2 The engine will not start
NOTESOnly consult this customer complaint after a complete check with the diagnostic tool.
Check that the fuel tank is correctly filled and that the fuel is correct: run TEST 13 Diesel fuel conformity check.
Check the levels of engine oil and coolant.
Check the air inlet circuit by running TEST 5 Inlet circuit check.
Is the catalytic converter clogged or damaged?Replace the catalytic converter (see MR
364 (Mégane II) or MR 370 (Scénic II),
Mechanical, 19B, Exhaust, Catalytic
converter: Removal - Refitting).
Check the air inlet circuit by running TEST 2 Electrical circuit check.
Check the electrical conformity of the heater plugs (the resistance value of the heater plug must be less than 2 Ω).
Is the timing set correctly? Carry out the necessary repairs.
Visually check the condition of the engine wiring harness.
YES
NO
NO
YES
A
DDCR_V44_ALP02/DDCR_V48_ALP02

13B-170
AFTER REPAIRCarry out a road test, then check with the diagnostic tool.
V4 MR-372-J84-13B000$140.mif
DIESEL INJECTION
Fault finding – Fault finding charts13B
InjectionDDCR
Vdiag No.: 44, 48
ALP3 The engine starts with difficulty, or starts then stalls
NOTESOnly consult this customer complaint after a complete check with the diagnostic tool.
Check that the fuel tank is correctly filled and that the fuel is correct by running TEST 13 Diesel fuel conformity
check.
Check the levels of engine oil and coolant.
Check the air inlet circuit: run test 5 Air inlet circuit check.
Is the catalytic converter clogged or damaged?Replace the catalytic converter (see MR 364
(Mégane II) or MR 370 (Scénic II),
Mechanical, 19B, Exhaust, Catalytic
converter: Removal - Refitting).
Check the electrical conformity of the heater plugs (the resistance value of the heater plug must be less than 2 Ω).
Is the timing set correctly? Carry out the necessary repairs.
Is the compression in order? Carry out the necessary repairs.
YES
NO
NO
YES
NO
YES
A
DDCR_V44_ALP03/DDCR_V48_ALP03

13B-179
AFTER REPAIRCarry out a road test, then check with the diagnostic tool.
V4 MR-372-J84-13B000$140.mif
DIESEL INJECTION
Fault finding – Fault finding charts13B
InjectionDDCR
Vdiag No.: 44, 48
ALP9 Engine cut-out (stalling)
NOTESOnly consult this customer complaint after a complete check with the diagnostic tool.
Check that the fuel tank is correctly filled and that the fuel is correct by running TEST 13 Diesel fuel conformity
check.
Check the levels of engine oil and coolant.
Check that the engine has not sucked up its oil (engine racing).
Check the air inlet circuit by running TEST 5 Inlet circuit check.
Is the catalytic converter clogged or
damaged?Replace the catalytic converter (see MR 364
(Mégane II) or MR 370 (Scénic II), Mechanical, 19B,
Exhaust, Catalytic converter: Removal - Refitting).
Visually check the condition of the engine wiring harness.
Check the air inlet circuit by running TEST 2 Electrical circuit check.
Check the low pressure circuit by running TEST 1 Low pressure circuit check.
YES
NO
A
DDCR_V44_ALP09/DDCR_V48_ALP09

13B-186
AFTER REPAIRCarry out a road test, then check with the diagnostic tool.
V4 MR-372-J84-13B000$140.mif
DIESEL INJECTION
Fault finding – Fault finding charts13B
InjectionDDCR
Vdiag No.: 44, 48
ALP 13 Excessive consumption
NOTESOnly consult this customer complaint after a full check with the diagnostic tool.
Check that the fuel tank is correctly filled and that the fuel is correct by running TEST 13 Diesel fuel conformity
check.
Check the levels of engine oil and coolant.
Is the fuel temperature sensor leaking?Replace the fuel temperature sensor
(see MR 364 (Mégane II) or MR 370
(Scénic II), Mechanical, 13B, Diesel
injection, Rail pressure sensor:
Removal - Refitting).
Check the low pressure circuit by running TEST 1 Low pressure circuit check.
Check the injectors by running TEST 3 Injector check.
Visually check that there are no leaks on the high pressure circuit by running TEST 7 High pressure circuit
sealing check.
Check the air inlet circuit by running TEST 5 Inlet circuit check.
YES
NO
A
DDCR_V44_ALP13/DDCR_V48_ALP13