ABS RENAULT SCENIC 2008 J84 / 2.G Electrical Equipment - Multiplexing Workshop Manual

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MULTIPLEXING
Fault finding - Introduction
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V4 MR-372-J84-88B050$100_eng.mif
MULTIPLEX NETWORK OPERATION TEST
This step is the essential starting point for any computer fault finding procedure.
It ensures that the network is correctly connected at the terminals of each computer and that the signal is correctly
sent to it and received by it. On the Scénic II ph2, this function also reads the number of faults present on the
computers.
The multiplex network test function is executed automatically after vehicle selection by the user.
After the network check, the other functions become accessible.
MULTIPLEX NETWORK TEST PROCEDURE
–Establish dialogue with the computers storing the vehicle configuration (read identification).
–Vehicle configuration read on the two computers that hold the multiplex network configuration (airbag and UCH
on the SCENIC II ph2).
–List of computers that can support fault finding read from the two computers that hold the multiplex network
configuration.
–Computer interrogation.
–Physical (electronic) measurements on the multiplex line network. Vehicle computer power supply for fault finding:
insert the vehicle card in the card reader.
Press and hold (over 5 seconds) the Start button in the absence of start conditions (for example: selecting a gear).
Connect the diagnostic tool and perform the required operations.
IMPORTANT
To supply the discharge bulb computer, switch on the dipped headlights.

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MULTIPLEXING
Fault finding - Introduction
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V4 MR-372-J84-88B050$200_eng.mif
MULTIPLEXING
Multiplexing enables signals to be sent between different computers on the vehicle, such as:
1UPC.
2Injection computer.
3BVA computer.
4LPG or CNG computer.
5ABS/ESP computer.
6UCH.
7Electric steering column lock.
8Automatic parking brake computer.
9Parking distance control computer (depending on version).
10 Electric power-assisted steering system.
11 Instrument panel.
12 Diagnostic socket.
13 ITS or Multimedia interface unit (depending on version).
14 Climate control computer.
15 Driving school unit (depending on vehicle).
16 Airbag/pretensioner computer.
MR-372-J84-88B050$200_eng.mif

MULTIPLEXING
Fault finding - Operating diagram
88B - 7
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V4 MR-372-J84-88B050$300_eng.mif
MULTIPLEXING
Fault finding - Operating diagram
1UPC.
2Injection computer.
3BVA computer.
4LPG or CNG computer.
5ABS/ESP computer.
6UCH.
7Electric steering column lock.
8Automatic parking brake computer.
9Parking distance control computer (depending on
version).
10Electric power-assisted steering system.
11Instrument panel.
12Diagnostic socket.
13ITS or Multimedia interface unit (depending on
version).
14Climate control computer.
15Driving school unit (depending on vehicle).
16Airbag/pretensioner computer.
MR-372-J84-88B050$300_eng.mif

MULTIPLEXING
Fault finding - Features
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V4 MR-372-J84-88B050$400_eng.mif
MULTIPLEXING
Fault finding - Features
To improve the performances of vehicles, more
computers are needed to share more information in
order to achieve optimal operation.
With multiplexing, numerous signals can be sent from
one computer to several others via a single electrical
connection.
Solution without multiplexing
Example: each computer would have to have its own
electrical connection to deal with vehicle speed signals
coming from the ABS. The number of connections
increases when there are more signals to be
communicated.Solution with multiplexing
In this instance, the vehicle speed signal is distributed
from the ABS computer to as many computers as
require it on a single electrical connection. All other
signals are transmitted via this connection as well.
Thus there is only one connection regardless of the
number of signals to be exchanged.
Advantages of multiplexing
●Reduction in costs as there is a reduction in
wire length and there are fewer connectors.
●Less wiring,
●Increased reliability due to there being fewer
connectors.
●Easier to locate a faulty component in some
cases.
Multiplex operation
The operation of a multiplex network can be compared
to an underground line which transports a number of
passengers. All the passengers use the same line
even though they get on and off at different points and
they take different trains depending on when they
started their journeys.
The multiplex network operates in a very similar way.
MR-372-J84-88B050$400_eng.mif

88B - 11
MULTIPLEXING
Fault finding - Configuration
88B
V4 MR-372-J84-88B050$600_eng.mif
MULTIPLEXING
Fault finding - Configuration
MULTIPLEX NETWORK CONFIGURATION
The tool displays the UCH and Airbag configurations.
The Configuration screen consists of two tabs for displaying and modifying:
–The first tab: Multiplex network configuration indicates the multiplex network version and the list of computers
defined as present on the multiplex network.
–The second tab Configuration of computers supporting fault finding indicates the relevant diagram number,
and the list of computers defined as able to support fault finding with the CLIP tool.
NOTESThe configuration is entered with the ignition on; apply the forced + after ignition
feed procedure (see Introduction).
It can be run from the multiplex network test results screens.
WARNING
Enter the correct diagram version number,
–Scénic II ph1: version 1.
–Scénic II ph2: version 2 with ITS (Vdiag 04) navigation computer.
–Scénic II ph2: version 3 with 4R or other navigation computer (Vdiag 24) or without navigation computer.
–Scénic II ph2: version 4 with LPN navigation computer.
First repair the computers containing the multiplex network configuration (airbag and UCH) to be able to
display the screen with the multiplex network configuration diagram for the diagnosed vehicle.
IMPORTANT
A computer connected to the multiplex network but not declared as being among the computers containing the
multiplex network configuration will not be checked in the multiplex network test.
Correct the configuration by declaring the computer as present if it is absent in the Airbag and UCH computer.
Carry out the multiplex network test again after modifying the configurations.
MR-372-J84-88B050$600_eng.mif

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MULTIPLEXING
Fault finding - Configuration
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Configuration screen
Make sure that the information displayed on the two tabs is correct.
The same configuration information for the two computers is essential for displaying the network topology.
Computer Multiplex network configurationConfiguration of computers that
can support fault finding
Injection PRESENT YES
ABS or ABS/ESP PRESENT YES
UCH PRESENT YES
Automatic gearbox connection PRESENT or ABSENT (option) YES or NO (option)
Instrument panel PRESENT YES
LPG PRESENT or ABSENT (option) YES or NO (option)
Steering lock PRESENT NO
Electric power-assisted steering PRESENT YES
Protection and Switching Unit PRESENT YES
Climate control (regulated) PRESENT or ABSENT (option) YES or NO (option)
Central Communication Unit* PRESENT or ABSENT (option) YES or NO (option)
Driving school unit PRESENT or ABSENT (option) NO (cannot support fault finding)
Airbag PRESENT YES
Automatic parking brake PRESENT or ABSENT (option) YES or NO (option)
Parking Distance Control** PRESENT or ABSENT (option) YES or NO (option)
Xenon bulbs ABSENT YES or NO (option)
Radio*** ABSENT YES
Multimedia interface*** PRESENT YES
*IMPORTANT:
NAV 4R ABSENT YES
ITS PRESENT YES
Others ABSENT NO

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MULTIPLEXING
Fault finding - Interpretation of faults
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FAULTY COMPUTER
NOTES–Make sure the computers installed in the vehicle are the correct type and are
compatible with the Scénic II ph2.
–Check the power supply of the computers (earth, + battery, + accessories or + after
ignition).
Make sure that the computer wake-up mode is in full working order on the vehicle and properly assimilated by the
computers.
The wake-up mode is:
–timed power supply: UCH, instrument panel.
–+ accessories feed: Protection and Switching Unit, Heating and Air Conditioning System, Central
Communication Unit.
–+ After ignition feed: Injection, ABS/ESP, airbag, Electric Power-Assisted Steering, Automatic
Transmission, LPG/Natural Gas Fuel, Steering column lock, Driving School Unit, Automatic Parking
Brake, Parking Distance Control.
–+ After ignition + dipped headlights: Xenon bulbs.
IMPORTANT
Only establish dialogue with the discharge bulbs with + after ignition and the dipped headlights on.
–Switch to computer diagnostics mode.
Attempt to establish dialogue with computers.
●No dialogue from computers to diagnostic tool: see ALP 1
No dialogue with the computer or computers not communicating with the diagnostic tool.
Check the connections to the computers and that there are no open circuits.
If there is a repair procedure (see Technical Note 6015A, Repairing electrical wiring, wiring:
precautions for repairs), repair the connectors, otherwise change them.
●The computers only produce partial information when identified:
Check in the MR or World Vehicle Database to see that the computer really is compatible with the
Scénic II ph2.
Make sure the CLIP diagnostic tool update is recent enough to handle Scénic II ph2 faults.
If after these tests no faults or open or short circuits have been detected, contact your Techline.
AFTER REPAIRRun the multiplex network test again using the diagnostic tool.
Clear the stored faults on all the computers connected to the network.
Deal with any other faults.

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MULTIPLEXING
Fault finding - Interpretation of faults
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V4 MR-372-J84-88B050$700_eng.mif
MULTIPLEX NETWORK NOT OPERATIONAL (CONTINUED)
120 ΩΩ Ω Ω
± 10 Ω
Open circuit on one or two lines.
Disconnect the airbag and check connections 133B and 133C between the diagnostic
socket (225) and the airbag (756).
Is the multiplex connection correct?
YESCheck that the resistance is approximately 120 ΩΩ Ω Ω
± 10 Ω
between the two network connections on the airbag computer:
–If the resistance is not approximately 120 ΩΩ Ω Ω
± 10 Ω, contact
Techline.
–If the resistance is 120 ΩΩ Ω Ω
± 10 Ω, check the continuity and
absence of interference resistance of connections 133B
and 133C between the diagnostic socket (225) and the UCH
(645).
If there is a repair procedure (See Technical Note 6015A,
Repairing electrical wiring, Multiplex: Multiplex
network, Repair).
Check that the resistance is approximately 120 ΩΩ Ω Ω
between the
two network connections on the UCH computer:
–If the resistance is not approximately 120 ΩΩ Ω Ω
, contact
Techline.
Repair the multiplex connection between the diagnostic socket
and the airbag.
If there is a repair procedure (See Technical Note 6015A,
Repairing electrical wiring, Multiplex: Multiplex network,
Repair).
If the fault is still present, contact your Techline.
NO
AFTER REPAIRRun the multiplex network test again using the diagnostic tool.
Clear the stored faults on all the computers connected to the network.
Deal with any other faults.

88B - 20
MULTIPLEXING
Fault finding - Fault Finding Chart
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V4 MR-372-J84-88B050$900_eng.mif
MULTIPLEXING
Fault finding - Fault Finding Chart
ALP 1 No dialogue with computers
NOTESVehicle computer power supply for fault finding:
insert the vehicle card in the card reader.
Press and hold (over 5 seconds) the Start button in the absence of start conditions (for
example: selecting a gear).
Connect the diagnostic tool and perform the required operations.
IMPORTANT
To supply the discharge bulb computers, switch on the dipped headlights.
Use Technical Note Wiring diagram, Scénic II ph2.
Try the diagnostic tool on another vehicle.
Make sure the tool has a more recent update than CD 64.
Check:
–The connection between the diagnostic tool and socket (connection and cable in good condition).
–The computers' power supply.
–The engine compartment and passenger compartment fuses.
MR-372-J84-88B050$900_eng.mif

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MULTIPLEXING
Fault finding - Fault Finding Chart
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ALP 1
CONTINUED 1
NOTESVehicle computer power supply for fault finding:
insert the vehicle card in the card reader.
Press and hold (over 5 seconds) the Start button in the absence of start conditions (for
example: selecting a gear).
Connect the diagnostic tool and perform the required operations.
IMPORTANT
To supply the discharge bulb computers, switch on the dipped headlights.
Use Technical Note Wiring diagram, Scénic II ph2.
Check that the CLIP sensor is supplied by the following connections: BP32 (+ 12 V), NAM and MAM (earths) on
the diagnostic socket. If the check is correct go to the next step according to the type of sensor used:
1. Renault fault finding sensor (with wire connection only):
displayed by the two red diodes on the sensor coming on.
Check that the CLIP sensor is supplied by the computer's USB port (red diode). If it is not, try with another cable,
another sensor or another clip in order to determine the defective component.
Make sure that the CLIP sensor is communicating properly with the vehicle's computers; this can be seen by the
two green diodes on the sensor lighting up. If not, check that the test conditions have been met (+ after ignition
feed, vehicle selection, etc.) otherwise apply the electrical checks below.
green LEDs red LEDs
multiplex line Vehicle supply through diagnostic socket
ISOSensor supply through USB port