Page 17 of 348

17B-17V7 MR-413-X44-17B000$030.mif
PETROL INJECTION
Fault finding – System operation17B
SIM 32 Injection
Program no.: D3
Vdiag No.: 44, 4C, 50
and 54
Summary table of malfunction modes:
Types SpecialEffects on the
engineCustomer complaints
Electrical
faults on
resistor or
wiringThermostat
faults–Open short
circuit
–Short circuit to
+ 12 V0%Coolant temperature
≈ 110˚C, limited
performance, low
temperature
reference value.Overheating warning light
comes on at each first
opening, high temperature on
instrument panel, fan
assembly 1 activated.
–Short circuit
100%Coolant temperature
≈ 90˚C, limited
performance, low
temperature
reference value.Normal operation for
customer but performance
limited by 10 to 20%.
Sensor
faults–All
Low
temperature
modeForced low
temperature mode,
with no limited
performance.No visible effect, impact on
fuel consumption with
permanent low
temperature operation.
Thermostat
faults
detectedNominalNo change of mode
when requested.Overheating warning light
lighting on first opening,
display of an additional
square if the mode is
changed.
Non-
electrical
faultsThermostat
faults
detected–Thermostat
stuck in closed
positionAll modesNo cooling, engine
overheating, engine
damage.Instrument panel display,
overheating warning, torque
reduction.
–Thermostat
stuck in open
position
All modesSlow increase in
temperature.Overconsumption of petrol
when cold, unsuitable
passenger compartment
temperature, possible
performance reduction when
cold.
Page 18 of 348
17B-18V7 MR-413-X44-17B000$030.mif
PETROL INJECTION
Fault finding – System operation17B
SIM 32 Injection
Program no.: D3
Vdiag No.: 44, 4C, 50
and 54
d. Cooling:
Engine cooling is performed by one or two fan assemblies (depending on the vehicle layout). The injection computer
sends a request to the UPC via the multiplex network to activate the cooling fans (Clio III and Modus).
For the new Twingo, the injection computer manages the fan assembly or assemblies.
Note:
In addition to the engine requirements, the injection computer centralises the cooling requirements for the Air
conditioning and BVA/BVR functions.
The switching thresholds depend on whether high/low temperature mode is being used.
In high temperature management:
Engine running
Fan assembly 1 Fan assembly 2 Air conditioning Overheating
ON> 110˚C > 115˚CWith authorisation> 120˚C
OFF< 105˚C < 113˚C > 118˚C < 118˚C
Page 19 of 348

17B-19V7 MR-413-X44-17B000$040.mif
17B
SIM 32 Injection
Program no.: D3
Vdiag No.: 44, 4C, 50
and 54
Injection computer:
This is located on the right-hand side of the engine compartment on the battery mounting.
Fuel vapour recirculation solenoid valve:
This is located on the left-hand side of the engine compartment, behind the engine mounting.
Upstream oxygen sensor:
This is located on the exhaust pipe, downstream of the turbocharger.
Downstream oxygen sensor:
This is located on the exhaust pipe, upstream of the catalytic converter.
Pinking sensor:
The sensor is located underneath the inlet manifold behind the oil dipstick.
Oil pressure sensor:
This is located under the exhaust manifold to the left of the engine compartment.
Turbocharger:
The turbocharger is located after the exhaust manifold.
Turbocharger pressure sensor:
The turbocharger pressure sensor is fitted to the air circuit between the turbocharger and the motorised throttle
valve.
Ignition coil:
This is located on the right-hand side of the rocker cover.
Motorised throttle valve:
The damper valve is located to the right of the inlet manifold.
TDC sensor:
This sensor is located on the flywheel.
Refrigerant pressure sensor:
This sensor is located on the coolant circuit.
Engine coolant temperature sensor:
This sensor is located on the cylinder head near the engine thermostat housing.
PETROL INJECTION
Fault finding – List and location of components
Page 20 of 348
17B-20V7 MR-413-X44-17B000$040.mif
PETROL INJECTION
Fault finding – List and location of components17B
SIM 32 Injection
Program no.: D3
Vdiag No.: 44, 4C, 50
and 54
Air temperature sensor:
The air temperature sensor is located between the air filter and the motorised throttle valve.
Catalytic converter:
The catalytic converter is located on the exhaust pipe at the exhaust manifold outlet.
Cruise control/speed limiter on/off switch:
This switch is located inside the passenger compartment to the left of the steering wheel near the lighting rheostat.
Fan unit relay:
The relay is located on the cooling radiator.
Accelerator potentiometer:
The potentiometer is located on the accelerator pedal.
Clutch pedal switch:
The switch is located on the clutch pedal.
Inlet air temperature sensor:
This sensor is located underneath the inlet manifold near the dipstick (except D4FT).
Page 21 of 348
17B-21V7 MR-413-X44-17B000$050.mif
17B
SIM 32 Injection
Program no.: D3
Vdiag No.: 44, 4C, 50
and 54
RV* / LV*: Cruise control/Speed Limiter1 - Injection computer 16 - Upstream sensor signal
2 - RV* / LV* buttons 17 - Ignition command
3 - Multiplex network 18 - Bleed canister command
4 - Turbocharger 19 - Fuel pump command
5 - Motorised throttle 20 - Downstream sensor signal
6 - Manifold pressure 21 - ESP computer
7 - Injector command 22 - Rev counter computer
8 - Clutch Pedal 23 - ABS computer
9 - Brake pedal 24 - Instrument panel computer
10 - Accelerator pedal 25 - Sequential gearbox computer
11 - Refrigerant fluid pressure 26 - AIRBAG computer
12 - Air conditioning compressor command 27 - Vehicle speed sensor computer
13 - Engine cooling fan assembly command 28 - Air conditioning computer
14 - Flywheel signal 29 - UCH computer
15 - Pinking signal 30 – Turbocharging pressure
PETROL INJECTION
Fault finding – Functional diagram
Page 22 of 348

17B-22V7 MR-413-X44-17B000$060.mif
17B
SIM 32 Injection
Program no.: D3
Vdiag No.: 44, 4C, 50
and 54
SYSTEM OPERATION
Composition
The injection system consists of the:
–accelerator potentiometer,
–TDC sensor,
–air temperature sensor,
–inlet manifold pressure sensor,
–+ turbocharging pressure sensor,
–coolant temperature sensor,
–refrigerant pressure sensor,
–upstream oxygen sensor,
–downstream oxygen sensor,
–cruise control switch (fitted according to the vehicle equipment level),
–cruise control on/off switch (fitted according to the vehicle equipment level),
–brake light switch,
–clutch pedal switch,
–fuel vapour absorber,
–injection computer,
–motorised throttle valve,
–four injectors,
–ignition coil,
–pinking sensor.
Additional components on D4FT 780:
–Turbocharging
–Oil vapour rebreathing circuit de-icing system
–OCS - Customised oil change interval
Computer
SIEMENS type "SIM32" 112-track computer controlling the injection and the ignition. Multipoint injection in
sequential mode.
Connections with the other computers, known as "Intersystem connections":
–ESP (fitted depending on vehicle equipment level).
–Passenger Compartment Control Unit (UCH).
–Gearbox Computer: BVR sequential gearbox (if fitted to the vehicle).
–Instrument panel.
–Airbag.
–ABS (if fitted to the vehicle).
–Rev counter instrument.
–Air conditioning.
PETROL INJECTION
Fault finding – Features
Page 23 of 348

17B-23V7 MR-413-X44-17B000$060.mif
PETROL INJECTION
Fault finding – Features17B
SIM 32 Injection
Program no.: D3
Vdiag No.: 44, 4C, 50
and 54
Engine immobiliser
The SIM 32 computer manages an engine immobiliser program:
–The Verlog 4 type immobiliser function is managed by the UCH computer and the engine management computer.
Before any customer request, the engine management computer and UCH exchange authentication frames via the
multiplex network to determine whether or not to start the engine.
After more than five consecutive failed authentication attempts, the engine management computer goes into
protection (antiscanning) mode and no longer tries to authenticate the UCH. The engine management computer only
exits this mode if the following sequence of operations is respected:
–the ignition is left on for at least 60 seconds,
–the signal is cut off,
–the injection computer self-feed deactivates when it should (the time varies according to engine coolant
temperature.
Following this sequence of operations, a single authentication attempt is authorised. If this fails again, repeat the
sequence of operations described above.
If the engine management computer still fails to unlock, contact the Techline.
Impact detected
If an impact has been stored by the injection computer (ET077 Impact detected), switch off the ignition for
10 seconds, then switch it back on so that the engine can be started. Then clear the faults using command RZ001
Fault memory.
Fuel supply
Fuel is supplied by the fuel pump. It is controlled each time the ignition is switched on, for 1 second, to provide a
certain pressure level in the circuit, and thereby achieve correct engine starting, particularly if the vehicle has not
been used for a long time. When the engine is running, the fuel pump relay is always controlled.
Injection
The injectors are controlled according to several modes. In particular, the engine is started in semi-full group mode
(injectors 1 and 4, then injectors 2 and 3 simultaneously), to ensure a correct start whether or not it is correctly
phased, then it enters sequential mode.
It can sometimes, though rarely, happen that the engine starts when incorrectly phased.
Then, after it has changed to sequential injection mode and as long as the cylinder 1 recognition program has not
taken place, the injectors are offset by two cylinders: injection occurs in the order 4-2-1-3 instead of the expected
order 1-3-4-2.
Injection timing is continuously calculated. It can be zero in the event of cut-off whilst decelerating or overrevving for
example.
Page 24 of 348

17B-24V7 MR-413-X44-17B000$060.mif
PETROL INJECTION
Fault finding – Features17B
SIM 32 Injection
Program no.: D3
Vdiag No.: 44, 4C, 50
and 54
Air supply
The idle speed regulator performs all of the calculations that allow the idle speed actuator, the motorised throttle, to
be controlled physically. The functional component of the regulator is adaptive (variation programming and ageing).
If the idle speed regulation conditions are met, the status ET054 Idle speed regulation is "Active", and the idle
speed regulator continually positions the motorised throttle to maintain the engine speed at its idle reference value.
The motorised throttle opening ratio necessary to comply with the speed setpoint is then given by parameter PR091
Idle speed regulation theoretical OCR*.
The PR090 Idle speed regulation programming value is a stored parameter designed to program engine
variations and engine wear and tear for the idle speed regulator. The programming is carried out only when the
engine is idle and warm, and no electrical consumer (air conditioning, fan assembly, power assisted steering) is
operating. Therefore it adjusts slowly.
Idle speed
The idle speed setpoint is dependent on:
–the coolant temperature,
–the emission control programs,
–air conditioning requirements,
–the position of the gear lever,
–any power-assisted steering operation,
–the passenger compartment heating resistors,
–the oil temperature (engine protection),
–the electric power balance (engine speed is increased by 160 rpm maximum if the battery voltage remains below
12.7 V).
Ignition
Advance is calculated for each cylinder, and is limited between - 23˚ to + 72˚, and includes possible corrections due
to pinking.
Anti-pinking correction is the maximum advance value taken from the advance of one of the cylinders. If none of the
cylinders is pinking, this correction is zero.