dashboard BMW 7 SERIES LONG 2003 E66 MOST Bus Diagnosis Workshop Manual

10
MOST Bus Diagnosis
CD Changer Audio (CDC)
The CD changer is a slave control unit in the MOST framework.
Navigation System (NAV 01)
The control unit of the navigation system has controller tasks and slave functions in the
MOST framework.
Slave Control Units
The following control units are slave control units:
 Kombi (control unit of the instrument cluster)
AVT
 LOGIC7
 SVS Speech processing system
 Telephone
 MMC
Component Locations
Located in the dashboard assembly:
 Control Display
 CD Changer
 ASK
 Kombi
 OPPS Connector
Located in the luggage compartment, rear left:
 Logic 7
 SVS
NAV
 MMC
 Telephone
Located in the C pillar left side:
AVT

18
MOST Bus Diagnosis
Status Wakeup
MOST control modules require high current during standby operation and must be discon-
nected or put in sleep mode to prevent the vehicle battery from being discharged. In case
of a fault on the the MOST network that continuously wakes up, the entire MOST bus will
be woken up. The Control Display will wake up the CAN Bus and all the vehicle busses will
be woken up. This will lead to battery discharge.
It is of great benefit to know which module initiated the wake up call. In order to find out
which MOST node woke up the MOST bus, the following procedure is performed:
In Control Unit Functions, press “STATUS WAKEUP”
Three different response are possible:
 Control Module woke up
 Control Module woken up
 Control Module not initialized
The Control Module with the status “Control Module woke up” is the module that woke up
the rest of the MOST bus.
This diagnosis only informs which control module woke, not the reason for the wake up,
diagnostic testing should be performed on the control module and related equipment.
Hints for Vehicle Equipment Identification
 
CDC - Look on passenger side of dashboard above glovebox.
 Logic 7 - Look for speaker grills on rear doors
Look on left side of trunk for
large amp.
 MMC - Look on left side of trunk.
Workshop Hint
Telephone modules may be swapped from vehicle to vehicle
for testing purposes, however if the original telephone mod-
ule is not returned to the original vehicle the Emergency func-
tions will not operated properly.
In case of an accident, information regarding location and
VIN will not be correct therfore help will not be dispatched.