NAVIGATION SYSTEM
E9
CIRCUIT OPERATION
2
REV: 09/2001
GPS Antenna (Z292)
The GPS Antenna (Z292) is located underneath the
air intake plenum and is connected to the Navigation
Computer (Z289) via a single co–axial cable and
passes signals received from the GPS satellites to
the Navigation Computer (Z289) for processing.
It is possible for the antenna to lose the signals from
the satellites in hilly or tree lined areas, built up
areas with tall buildings, multi–storey car parks,
garages, tunnels, bridges and during heavy
rain/thunderstorms. When the signal is lost, the
navigation computer will continue to give guidance
using memory mapped data from the CD map until
the signal is restored.
Display and Control Unit (Z291)
The Display and Control Unit (Z291) is located in the
centre of the fascia. The unit comprises of a colour
Liquid Crystal Display (LCD) screen and controls to
operate the navigation functions. The Display and
Control Unit (Z291) comprises four control switches,
one rotary press menu control and one status LED.
A photosensor is used to control the brightness of
the screen in day and night time conditions (Refer to
the workshop manual for detailed operation).
Diagnostics Mode
The navigation system may be put into a on–board
diagnostics mode (service mode) by selecting the
’settings’ menu from the main menu then pushing
and holding the menu key for about 10 seconds. The
service mode has four main functions:
1.
To check that components are fitted and to
determine their hardware/software levels.
2.
To perform a quick ’health check’ of the major
input signals to the system.
3.
To check for correct operation of the display and
control unit keys.
4.
To check the status of the GPS reception.
Selecting the on–board monitor item from the service
mode menu causes the version info to be displayed.
The screen displays the software and hardware level
of the display and control unit together with the
diagnostics and bus index. The supplier of the unit is
also displayed as a number code defined by BMW.
The system queries the display and control unit
before displaying the information on the screen. If
the unit responds with
Software Hardware levels this implies that the
component is connecting to at least power, ground
and K–bus.