88B-20
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.
V3 MR-413-X44-88B000$070.mif
88B
MULTIPLEX NETWORK NOT OPERATIONAL
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.
Switch off the ignition.
Finding the fault
type
NOTESObtain a copy of the multiplex network diagram for the
vehicle.
(Diagnostic socket diagram).
Measure the resistance of component 225 between the following connections:
•Connection code 133B
•Connection code 133C
What is the value obtained?
0 ΩΩ Ω ΩThe two lines are in short circuit (see Introduction - Repair advice).
60 ΩΩ Ω Ω
± 10 ΩΩ Ω Ω
Check first that the computers storing the configuration (Airbag and UCH) are
correctly supplied:
–check for earth on connection NAP, and for +12 V supply on connection AP25 on
component 756.
–check for earth on connections MAM and NAM, and for +12 V supply on
connections AP7, AP43, BP3, BP6, BP15, BP19, BP49 on component 645.
BETWEEN 70 ΩΩ Ω Ω
AND 110 ΩΩ Ω ΩFor each connection 133B and 133C, check that there is no interference resistance
and then check that there is no short circuit to earth or to the + battery feed.
120 ΩΩ Ω Ω
± 10 ΩΩ Ω Ω
Open circuit on one or two lines.
Disconnect the airbag and check the multiplex connection between the diagnostic
socket and the airbag.
Is the multiplex connection correct?
MULTIPLEXING
Fault finding – Interpretation of faults
