88B - 23
MULTIPLEXING
Fault finding - Fault Finding Chart
88B
V4 MR-372-J84-88B050$900_eng.mif
ALP 1
CONTINUED 3
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 the following connections on the diagnostic socket:
BP 32 + battery feed
NAM and MAM Earth
If the connection or connections are faulty and there is a repair procedure (see Technical Note 6015A, Electrical
wiring repair, Wiring: Precautions for repair), repair the wiring, otherwise replace it.
Computer connected to multiplex line V
If the fault is still present, check the continuity and the insulation of the following connections:
Multiplex line H (133B of component 225)
Multiplex line L (133C of component 225)
Use a multimeter to check that the voltages at the terminals of component 225 are approximately:
–2.5 V between multiplex line H (133B) and the earth (NAM and MAM) (Average values)
–2.5 V between multiplex line L (133C) and the earth (NAM and MAM) (Average values).
Refer to the Introduction - “Repair advice” to detect a short circuit on the vehicle's multiplex network.
