88B - 14
MULTIPLEXING
Fault finding - Interpretation of faults
88B
V4 MR-372-J84-88B050$700_eng.mif
MULTIPLEXING
Fault finding - Interpretation of faults
FAULTY SEGMENT ON THE MULTIPLEX NETWORK
NOTESFirst check that the computer at the end of the faulty segment is properly
powered (earth, + battery, + accessories or + after ignition).
Always check the computer conformity.
If the Protection and Switching Unit computer is not detected, apply the appropriate
fault finding procedure (see 87G, Engine Compartment Connection Unit, Fault
Finding Chart, ALP1).
IMPORTANT
The tool may not be able to pinpoint the faulty segment(s) exactly. It then suggests
several segments that could be faulty. In this event, repair the segment closest to the
diagnostic socket.
Isolate the faulty segment by disconnecting both ends of the segment. Check the condition of the connections (see
Technical Note 6015A Repairing electrical wiring, Multiplex: Multiplex network, Repair).
Check the continuity and insulation of the multiplex line H and multiplex line L lines between the two connectors
on the isolated segment.
Refer to the vehicle's multiplex network diagram for the allocation of tracks on the computers and connections.
Perform the necessary operations to check the continuity of the two lines (for example, replacing the wiring).
Make sure that the computer present in the vehicle is compatible with the Scénic II ph2 and that the signals it is
producing are correct.
Reconnect the segment.
Run the multiplex network test again using the diagnostic tool.
Is the segment still declared faulty?
NoEnd of fault finding.
Are there other faulty segments?
Yes
NoTest the multiplex network again to check the continuity and
insulation of the multiplex line H and multiplex line L lines
between the end of the faulty segment and the diagnostic
socket at connections 133B and 133C (see diagnostic
socket diagram).
Apply the same procedure to each segment.
Yes
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.
MR-372-J84-88B050$700_eng.mif
88B - 20
MULTIPLEXING
Fault finding - Fault Finding Chart
88B
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
