turn signal RENAULT SCENIC 2010 J95 / 3.G Engine And Pheripherals DCM 1.2 Injection Workshop Manual

13B-12V10 MR-372-J84-13B100$040.mif
13B
DCM 1.2 Injection
Program No.: 4D
Vdiag No.: 48, 4C, 50,
54, 58, 5C
System outline
The DCM1.2 injection system used on the K9K 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 takes place
when a current pulse is applied to the injector holders. The amount injected is proportional to the rail pressure
and the applied pulse length, and the start of injection is synchronised with the start of the pulse.
The system includes two subsystems, which have different fuel pressure levels:
–The low pressure circuit contains the tank, the diesel fuel filter, the transfer pump and the injector holder
return pipes,
–the high-pressure system includes the high-pressure pump, rail, injector holders and high-pressure pipes.
Finally, there are a certain number of sensors and regulating actuators for controlling and monitoring the entire
system.
Functions performed:
Function: Fuel supply management (timing, flow and pressure).
Quantity of fuel injected and injection timing setting
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 sensor (Crankshaft + Cam lobe for synchronisation),
–accelerator pedal sensor,
–coolant temperature sensor,
–rail pressure sensor,
–atmospheric pressure sensor,
–accelerometer,
–inlet manifold pressure sensor.
Specific vehicle / engine suffix details:
Modus
K9K 750 752 (Euro 3)Inlet manifold temperature and pressure sensor (a sensor which has two functions),
management by the turbocharger control solenoid valve inlet pressure.
K9K 766 (Euro 4)Either a flow sensor with an integrated temperature sensor or a temperature sensor
instead of a flow sensor with inlet manifold temperature sensor, inlet manifold pressure
sensor, management by turbocharger control solenoid valve programming.
K9K 768 (Euro 4)Flow sensor with integrated temperature sensor, inlet manifold pressure sensor,
management by the turbocharger control solenoid valve inlet pressure.
DIESEL INJECTION
Fault finding – Function

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DIESEL INJECTION
Fault finding – Function13B
DCM 1.2 Injection
Program No.: 4D
Vdiag No.: 48, 4C, 50,
54, 58, 5C
Angular position measurement
Engine speed sensor:
The angular position is measured using a magneto-inductive sensor triggered by machined teeth on the shaft
flywheel. This flywheel has sixty teeth, six degrees apart, minus two missing teeth that form a notch.
Cylinder reference sensor:
A second sensor (Hall effect) triggered by a machined tooth on the high pressure pump drive pulley (synchronised
with the camshaft), turning at half the engine speed, supplies a signal about the progress of the injection cycle.
By comparing the signals from these two sensors, the computer's APS module (Angular Position Subsystem) can
supply the entire system with the synchronisation factors, which are: the angular position of the flywheel, the engine
speed, the number of the active injector and the injection cycle timing.
This module also supplies the system with the engine speed signal.
New pump chamber filling procedure (pump boosting)
The pump lubrication goes through a booster cycle during which the pump is filled and pressurised before
"transferring" the diesel fuel to the rail.
This lubrication goes through a procedure called new pump chamber filling, which prevents starting for
approximately 10 seconds, which is the time required for filling the pump and starting. For vehicles with keys,
if the key is released before the end of this "initial starting" phase there is no need for a power latch phase to be
completed before a fresh attempt to start the vehicle.
This procedure is run after the first start in the factory, after a computer is replaced if the parameters relating to
the rail pressure have not been copied into the new computer, and also after reprogramming of the injection
computer.
Variable Low Capacity (VLC) output function
Because of the combination of several parameters such as the diesel fuel temperature, part wear, clogging of
the diesel filter etc., the system limit may be reached during its service life. If this happens, the rail pressure cannot
be maintained because the pump lacks the necessary capacity. If the pump lacks the necessary capacity, this
programming will therefore reduce the requested flow to a value that will enable the pressure monitoring system to
control the pressure again.
The customer may have noticed a loss of vehicle performance when this program is activated (depending on
the vehicle, this programming can be confirmed by ET563 Flow capacity function). This is normal operation of
the injection system.
Function: Air flow management
EGR valve control
K9K 766 and 768 (Euro 4) engines (fitted on Clio III and Modus) and K9K 724 (Euro 4) engines (fitted on
Mégane II and Scénic II) and K9K 740 engines (fitted on New Twingo) and K9K 800, 802 and 812 engines
(fitted on Kangoo 2):
The EGR (Exhaust Gas Recirculation) system consists of a DC proportional EGR valve, which incorporates
a valve position feedback potentiometer. The EGR valve is closed-loop controlled based on its position via
the potentiometer and/or based on changes in the estimated air flow.
K9K 750 and 752 (Euro 3) engines (fitted on Clio III and Modus):
The EGR system (Exhaust Gas Recirculation) consists of an EGR solenoid valve, which incorporates a valve
position feedback potentiometer. The EGR valve is closed-loop controlled based on its position via
the potentiometer and/or based on changes in the estimated air flow.

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13B
DCM 1.2 Injection
Program No.: 4D
Vdiag No.: 48, 4C, 50,
54, 58, 5C
High and low pressure pump:
The pump draws in fuel from the tank, which passes through a fuel filter and supplies the fuel injectors.
Injector rail:
The injector rail receives and redistributes fuel under high pressure to the injectors.
Solenoid injectors:
These injectors enable rapid, precise metering of the quantity of fuel injected, with excellent injection process
repetitiveness.
Catalytic converter:
Its role is to convert pollutant gases into harmless gases.
Heater plugs:
The heater plugs create a hot point in the combustion chamber to improve starting in low temperature conditions.
They are also used to improve idle speed stability under some conditions.
Turbocharger:
The turbocharger is used to supply the engine with more air.
Turbocharger control solenoid valve (K9K 724, 766, 802, and 812 only):
This solenoid valve controls the turbocharger wastegate.
Air flowmeter (if present on the vehicle):
The flowmeter measures the amount of fresh air which goes back into the engine.
EGR valve:
The exhaust gas recirculation enables nitrogen oxide (NOx) emissions to be reduced significantly.
Cruise control - speed limiter on - off switch:
This switch turns the cruise control/speed limiter on or off.
Accelerator pedal potentiometer:
The accelerator potentiometer informs the computer about the position of the accelerator pedal (engine load).
Clutch pedal switch:
The clutch pedal switch informs the computer about the pedal status.
TDC sensor:
The angular position is measured using a magneto-inductive sensor triggered by machined teeth on the flywheel.
This sensor gives the engine speed as well as the position of the crankshaft for injection.
Camshaft sensor:
This sensor gives a signal to perform the injection cycle.
When the piston of cylinder 1 is at top dead centre (TDC), it can be either at the end of the compression stroke
or at the end of the exhaust stroke. The camshaft sensor enables a distinction to be made between these two states.
Refrigerant pressure sensor:
Its role is to measure the refrigerant pressure in the air conditioning circuit.
Engine coolant temperature sensor:
The engine coolant temperature sensor informs the computer about the engine coolant temperature.
Water in diesel fuel sensor (New Twingo and Kangoo 2 only):
This sensor determines if there is water present in the diesel fuel.
DIESEL INJECTION
Fault finding – Role of components