2009 RENAULT TWINGO instrument panel

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88B
INTRODUCTION
Description of the multiplex network:
The multiplex network consists of a twisted pair of wires connected to several vehicle computers.
These two wires are called multiplex line H and multiplex line L.
Depending on the vehicle options, there is a single multiplex network.
–the Vehicle multiplex line (injection, anti-lock braking system/electronic stability program, instrument panel, air
conditioning, rev counter, sequential gearbox, UCH, airbag/pretensioners) is always present,
–the Multimedia multiplex line (navigation, radio, display, hands-free telephone) depending on the vehicle options.
Data is exchanged by the computers on the Vehicle multiplex line and Multimedia multiplex line networks at a
communication speed of 500 kbit/s.
The Vehicle multiplex line network has two computers, each with an internal resistance of 120ΩΩ Ω Ω

(network terminating resistors):
–the injection computer,
–the airbag computer.
The Multimedia multiplex line network has two computers, each with an internal resistance of 120ΩΩ Ω Ω

(network terminating resistors):
–the A2/A3 display,
–the radio.
PURPOSE
–The purpose of the multiplex network test is to determine the computers present on the vehicle's multiplex network
as well as the cause of possible inter-computer communication faults.
–It also serves to determine the functions installed in the vehicle which are often housed in various computers
(distributed functions, e.g.: Air conditioning, Security access, etc.).
–The test also checks the condition of multiplex network segments.
–The multiplex network test can also run fault finding on computers disconnected from the multiplex network; this
provides an overview of the vehicle's electronic layout. Note:
The Vehicle and Multimedia multiplex line networks support fault finding using the RENAULT tool.
MULTIPLEXING
Fault finding – Introduction

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MULTIPLEXING
Fault finding – Introduction88B
MULTIPLEX NETWORK TEST PROCEDURE
–Establish dialogue with the computers storing the vehicle configuration (read identification).
–Read the vehicle configuration in the two computers that store the multiplex network configuration (UCH and
Airbag) for the Vehicle multiplex line network.
–Read the vehicle configuration in the computer that stores the multiplex network configuration (A2/A3 display
computer) for the Multimedia multiplex line network.
–List of computers which support fault finding read from the two configuration computers.
–Computer interrogation.
–Physical (electrical) measurements on the multiplex line network.
IMPORTANT
There are three diagnostic lines, depending on the vehicle options:
Fault finding on the computer using the vehicle multiplex network:
–Injection systems,
–ABS or ABS/ESP or vehicle speed computer (depending on the vehicle equipment),
–UCH,
–Automatic transmission (depending on the vehicle equipment),
–Lighting (depending on the vehicle equipment),
–Instrument panel,
–Airbag/pretensioners,
–Climate control (depending on the vehicle equipment),
–Driving school unit (depending on the vehicle equipment),
–LPG injection (depending on the vehicle equipment).
Fault finding on computers using the multimedia multiplex network (depending on the vehicle equipment):
–Radio (R1-08 or R2-08),
–Multimedia interface (A2/A3 display),
–Multimedia connection (C-box).
Fault finding on the computer using the K line (depending on the vehicle equipment):
–Parking distance control and power-assisted steering.

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Multiplexing enables signals to be sent between different computers on the vehicle, such as:
119 Automatic transmission computer 756 Airbag pretensioners/computer
120 Injection computer 995 Electronic rev counter
247 Instrument panel 1094 ABS/ESP computer
419 Air conditioning computer 1222 Parking distance control computer
502 Power-assisted steering computer 261 Radio
645 UCH 225 Diagnostic socket
653 Multimedia interface (A2/A3 display) 1959 Multimedia connection (C-box)
1222 247 995
502
645
120 119 65310941959
225261419
756
MULTIPLEXING
Fault finding – List and location of components

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MULTIPLEXING
Fault finding – Operating diagram88B
Operating diagram of the CAN Vehicle network
Number Description
119 Automatic gearbox
120 Injection computer
247 Instrument panel
419 Air conditioning
502 Power-assisted steering
645 UCH
653 Multimedia interface
756 Airbags
995 Electronic rev counter
1094 ABS
1222 Parking distance control
OBD Diagnostic socket
E134 Splice
R107 Dashboard - front of engine connection
E133 Splice
120
010
11 123
5
6
7 89 OBDE134
E133 R107
645 1094119
419
995
247
653
1222 502 756
MULTIPLEXING
Fault finding – Operating diagram

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88B
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 should have its own electrical connection in order to use the vehicle speed signal sent by
the anti-lock braking system vehicle speed computer (depending on vehicle equipment). The number of connections
increases when there are more signals to be communicated.1ABS computer3Instrument panel
2Automatic gearbox computer4Injection computer
12
3
4
MULTIPLEXING
Fault finding – Function

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MULTIPLEXING
Fault finding – Function88B
Solution with multiplexing
In this case, the vehicle speed signal is shared by the anti-lock braking system vehicle speed computer (depending
on vehicle equipment), and as many computers as necessary via 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 weight due to wiring harness.
•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.1ABS computer3Instrument panel
2Automatic gearbox computer4Injection computer
12
3 4

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MULTIPLEXING
Fault finding – Configuration88B
CAN Vehicle 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.
Option: depending on equipment level
CAN Multimedia configuration screen Computer Multiplex network configurationConfiguration of computers that
can support fault finding
Injection (120) PRESENT YES
ABS/ESP (1094) PRESENT YES
Instrument panel (247) PRESENT YES
UCH (645) PRESENT YES
Airbag/pretensioners (756) PRESENT YES
Air conditioning (regulated) (419) PRESENT (option) YES (option)
Sequential gearbox (119) PRESENT (option) YES (option)
Power-assisted steering (502) ABSENT (option) YES (on K line) (option)
Rev counter (995) PRESENT (option) YES (option)
Parking distance control (1222) ABSENT YES (on K line)
A2/A3 display (653) PRESENT (option) YES (option)
Computer Multiplex network configurationConfiguration of computers that
can support fault finding
A2/A3 display (653) PRESENT YES
Radio R1-08 or R2-08 (261) PRESENT or ABSENT (option) YES or NO (option)

88B-23
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 faults88B
FAULTY COMPUTER
Vehicle multiplex network
NOTESMake sure that the computers installed in the vehicle are the correct type and are
compatible with the vehicle.
Check that the computers are correctly supplied (earth, + battery feed,
+ accessories feed or + after ignition feed).
Make sure that the computer wake-up mode is in full working order on the vehicle and is properly assimilated
by the computers.
The wake-up mode is:
–Timed supply: UCH,
–+ accessories feed: Air conditioning, ABS/ESP.
–+ after ignition feed: Injection, Airbag/Pretensioners, Sequential gearbox, Instrument panel.
In + accessories feed these computers will not appear.
–Switch to computer fault finding mode.
Attempt to establish dialogue with computers.
No communication from computers to diagnostic tool: see ALP 1
No communication with the computer or computers not communicating with the diagnostic tool.
Check the connections to the computers and that there are no open circuits.
Repair if necessary.
Computers are not displaying all the information on their identifications:
Check in the Workshop Repair Manual or the World Vehicle Database that the computer is compatible
with the vehicle.
Check that the CLIP diagnostic tool update is recent enough to be able to deal with faults on the vehicle.
If no faults or open or short circuits have been detected after these checks, contact Techline.