FAULT FINDING INTRODUCTION
General method
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01E-2
101EFAULT FINDING INTRODUCTION
General method
The Scénic II is a multiplexed vehicle equipped with a communications network operating at a speed of
500 kBauds.
This change has allowed a new optimisation of the electronic layout of the vehicle in two ways:
●Distribution of vehicle functions: the main computers present on the multiplex network manage several
functions (example: UCH: access - vehicle protection - lighting - wipers - passenger compartment heating - tyre
pressure monitor).
●Elimination of redundant sensors: the "steering wheel angle" signal used by the electronic stability program
is produced by the electric power assisted steering which then transmits it to the multiplex network. So the
steering wheel angle sensor used by the electronic stability program does not exist.
This change has also allowed fault finding on computers present on the multiplex network to be performed by the
main communication network of the vehicle (multiplex network) instead of a cable network dedicated to fault
finding (K / L lines).Warning:
Scénic II diagnostics can only be done with the CLIP fault-finding tool equipped with the vehicle diagnostic
probe (part no.: Elé. 1674).
Note:
The multiplex network of the vehicle is the main functional communication network of the vehicle. But
certain optional functions are still performed by track wires.
IMPORTANT
However, the Scénic II still uses two different physical fault finding media:
●The multiplex network: which allows fault finding of the following computers: instrument panel, electric
power assisted steering, airbag, automatic air conditioning, UCH, anti-lock braking system - electronic
stability program, protection and switching unit, injection.
●K / L lines diagnostic network: for fault finding on the following computers: automatic transmission,
automatic parking brake, discharge bulbs and parking assistance.
Some other computers, while connected to the vehicle's multiplex network, have their own "self-test" function:
central communications unit (Carminat), driving school unit or that cannot be diagnosed with the tool: steering
lock (governed by the UCH).
IMPORTANT
Computer supply for the fault finding procedure:
To run fault finding on the vehicle computers, proceed as follows:
●Vehicle card in card reader
●Press and hold start button (longer than 5 seconds) with start-up conditions not fulfilled,
●Connect the diagnostic tool and perform the required operations.
FAULT FINDING INTRODUCTION
General method
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01E-5
2 - Design innovations:
These innovations concern services which are already in use but which are implemented in a specific way on the
Scénic II:
AIR CONDITIONINGThis service is standard on RENAULT vehicles, only the distribution of tasks is
specific:
●Air conditioning: responsible for user intention (management of temperature for
controlled air conditioning) and for mixing and distribution of air in the passenger
compartment (manual and controlled air conditioning).
●UCH: responsible for the heating function.
●Injection: responsible for management of the air conditioning (cold cycle).
●Switching Protection Unit: responsible for the power required for air conditioning
(compressor and engine cooling fan).
WIPERSThe distribution of the function is as follows:
●UCH: responsible for driver's intention, management of the wiper stalk and the rear
screen wiper.
●Switching Protection Unit: responsible for the power required for the windscreen
wiper.
LIGHTINGThis function has already been described in Section 1 - Functional innovations. Refer
to this section for further information.
Note:
In the case of lighting without XENON bulbs, the Switching Protection Unit manages
the dipped headlights.
ENGINE
MANAGEMENT -
INJECTION This function is shared by two computers:●Injection: management of programming and information associated with engine
management, and of the speed regulation and limitation function.
●Protection and Communication Unit: management of the power required for engine
management. The Protection and Communication Unit also incorporates the fuel
pump relay and actuators controlled by cable by the injection computer.
