SECTION 06: ELECTRICAL
30
DOB 2490-2789 | X3-45 Commuter PA1605 Maintenance Manual (Final Version) – Sec 06 revised June 2017
Problem/symptom
Probable causes
Actions
Can network problem
(multiplex)
Module a53 not powered or
is defective
Engine ecm does not receive
the ignition signal
Engine ecm is not powered
If the vehicle does not start from the rear:
1. Verify that module a53 is powered:
a) Check the
diagnostics
menu of
driver information display (DID).
Select
fault diagnostics
and
electrical system
. The message
“no response moda53, active”,
indicates a power problem on the
module or a can network problem.
b) Check / reset circuit breaker cb5
c) Check / replace fuse f65
d) Probe gray connector on module to
see if it is powered.
2. Verify that the engine ecm is powered
and get the ignition signal
a) Check / reset circuit breaker cb8
check / replace fuse f74
b) Check / reset circuit breaker cb2
check / replace fuse f78
None of the multiplexed
functions are operating,
including the basic limp-
home functions (door
opening, flashers, wipers
in speed 1)
Note: the sunshades are
still functioning since
these are not multiplexed
The program version in the
mcm is different than the
program in the i/o modules
and the mcm is forcing all i/o
modules to stay inactive
1. Engage the auto-programming of the
i/o modules: turn the ignition switch to
the off position, flip the master cut-out
switch on the rear electrical panel to
off and on and then turn the ignition
switch back on. The letters can will
appear in the telltale lcd panel for
about 3 minutes everything shall get
back to normal once the letters can
are replaced with outside temperature
display
2.
Try disconnecting the green
connector on the mcm and reconnect
3.
Try disconnecting the mcm
completely, leave it disconnected and
see if the limp-home functions (start of
the vehicle from the engine
compartment, wipers speed 1,
flashers, etc ) are functioning
