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-78
AFTER REPAIRDeal with any faults declared by the diagnostic tool. Clear the computer fault memory.
Carry out a road test followed by another check with the diagnostic tool.
V4 MR-372-J84-13B000$062.mif
DIESEL INJECTION
Fault finding – Interpretation of faults13B
DDCR INJECTION
Vdiag No.: 44, 48
DF121
STOREDACCELEROMETER CIRCUIT
NOTESPriorities when dealing with a number of faults :
DF001 Coolant temperature sensor circuit,
DF002 Air temperature sensor circuit,
DF098 Fuel temperature sensor circuit,
DF003 Atmospheric pressure sensor circuit.
A fault on these sensors could lead to incorrect fault finding on the accelerometer.
Conditions for applying fault finding procedures to stored faults:
The fault is present with the engine idling.
Check the conformity of the injectors fitted to the vehicle in relation to the type of vehicle and engine number
(low, high or very high pressure injector).
Check the condition and connection of the accelerometer connector.
Repair if necessary.
Check the connection and condition of the brown 48-track connector B of the computer and check the sensor
shielding on track K1.
Repair if necessary.
Check the insulation, continuity and the absence of interference resistance on the following connections:
Sensor connector track 1 Track F1 computer connector B
Sensor connector track 2 Track G1 computer connector B
Repair if necessary.
Check that the C2I is correctly entered on the computer.
Check that the accelerometer is secured on the engine.
Disconnect and reconnect the accelerometer sensor to accomplish fast programming.
Carry out a road test followed by another check with the diagnostic tool.
If the fault is still present, replace the accelerometer.
13B-160V4 MR-372-J84-13B000$120.mif
DIESEL INJECTION
Fault finding – Tests13B
DDCR INJECTION
Vdiag No.: 44, 48
TEST 11 Turbocharger air chain
Check for the air filter
Check the replacement interval of the air filter on the maintenance booklet.
Compare the part numbers of the air filter fitted to the vehicle and that of the air filter recommended by the
manufacturer.
Check the air filter direction of fitting.
Is the air filter fitted to the vehicle correct?
Check the condition of the air filter
Visually inspect the condition of the filtering section of the air
filter.
Is either the air filter or its seal damaged?
Is the air filter fouled (does it contain a lot of impurities)?Replace the air filter (see MR 364
(Mégane II) or 370 (Scénic II),
Mechanical, 12A, Fuel mixture, Air
filter, Removal - Refitting).
Low pressure circuit check
Note:
Depending on the vehicle type, the best visual access will be
either from above or from below.
Visually inspect the condition of the following components:
– fresh air inlet scoop on the front panel of the vehicle,
– air inlet pipe to the air filter,
– air pipe of the filter until the compressor inlet,
– mountings of the air flowmeter.
Is one of these components incorrect (disconnected,
cut, bent, pierced or kinked pipes)?Replace the defective parts (see MR
364 (Mégane II) or 370 (Scénic II),
Mechanical, 12B, Turbocharging).
YESNO
YES
NO
YES
A
NO
DDCR_V44_TEST11/DDCR_V48_TEST11
13B-162V4 MR-372-J84-13B000$120.mif
DIESEL INJECTION
Fault finding – Tests13B
DDCR INJECTION
Vdiag No.: 44, 48
TEST 13 Diesel fuel conformity check
WARNING
– During this operation, it is essential to:
– refrain from smoking or bringing incandescent objects close to the work area,
– guard against petrol splashes caused by the residual pressure in the pipes,
– wear safety goggles with side guards,
– wear leaktight gloves (Nitrile type).
IMPORTANT
– To avoid any corrosion or damage, protect the areas on which fuel is likely to run.
– To prevent impurities from entering the circuit, place protective plugs on all fuel circuit components
exposed to the open air.
Preparations:
Weigh an empty 1300 ml plastic cup (part no. 77 11 171 413) with its cover (part no. 77 11 171 416) using
electronic scales such as those used in body paint workshops (for example: PANDA, part no. 77 11 224 995).
Record the weight of the empty plastic cup.
This type of plastic cup is used to prepare paint.
Take a 1 litre fuel sample from the diesel filter outlet (see MR 364 (Mégane II) or 370 (Scénic II), Mechanical,
19C, Tank, Fuel tank: Draining), using a pneumatic transfer pump (part no. 634-200) and place it in the 1300 ml
plastic cup.
Cover the plastic cup with its cover and let it settle for approximately2 minutes.
Is the fuel cloudy or does it
separate into two parts?Presence of water in diesel fuel, the fuel is not compliant.
Drain the fuel circuit, including the tank (see MR 364 (Mégane) or
370 (Scénic), Mechanical, 19C, Tank, Fuel Tank: Draining).
YES
A
NO
DDCR_V44_TEST13/DDCR_V48_TEST13
13B-195
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
ALP18 Oil leaks from the turbocharger
NOTESBefore analysing this customer complaint, check that there are no faults, and the
conformity (or otherwise) of the parameters and statuses, using the diagnostic
tool.
If the customer complaint is not eliminated, perform the following checks.
Check the area around the turbocharger
Note:
An oil leak does not correspond always to a fault of the turbocharger, the oil leak can arise from the area around
the turbocharger.
Depending on the vehicle type, the best visual access will be either from above or from below.
1. Do not start the engine.
Check the area around the turbocharger and identify the origin of the leaks.
Clean the oil traces on the turbocharger.
2. start the engine and let it warm up for several minutes.
IMPORTANT
If the air filter was previously removed, refit it before starting the engine (risk of aspirating foreign bodies into the
air inlet circuit).
Accelerate with no load several times, progressively increasing the duration before releasing the accelerator pedal.
Visually inspect the exterior condition of the fuel supply pipes and the turbocharger oil return and the area around it.
Identify the origin of the leaks.
Is an oil leak present at the air compressor inlet or outlet?
AB
YESNO
DDCR_V44_ALP18/DDCR_V48_ALP18