Navigation system

Function

The navigation system is an additional, optional feature of the on-board monitor system. The driver can display road maps at various scales on the on-board monitor. In addition, it is possible to enter a destination, for which the navigation computer calculates the most favorable route based on the current location.This route can then be shown on the map as required.

While driving, the computer provides visual information, based on the current location, in the form of turning arrows and acoustic indicators for the proposed route, such as turn-off information with the distance to the next junction as well as requests to merge into the correct lane in good time. If the driver does not follow this suggestion, the navigation computer will propose an alternative route.

The navigation computer located in the rear left of the luggage compartment features a CD drive in which a CD with the stored road maps is loaded.

The system is operated via the on-board monitor control panel, the navigation computer controls route planning, the acoustic indicators and visual displays are generated by the video module.

A GPS (satellite) receiver (GPS = Global Positioning System) supplies the current position.

In addition, the navigation computer receives information on the driving direction from a magnetic field sensor, the distance covered from the ABS control unit and whether reverse gear is engaged from the light module or back-up lights.

The system only operates when a road map CD is loaded and in the areas, for which maps are stored on the CD.

Note

Generally, care must be taken to ensure that no metal objects (e.g. umbrellas) are placed in the area of the rear window shelf, as they could impair operation.

Components

The navigation system consists of the following components and processes the following signals:

• Navigation computer with CD drive
  
• Road map CD
  The map CD contains a digitized road map. The navigation system can only operate when a road map CD is inserted.
  
• ABS control unit/speed sensor
  The navigation computer receives information from the ABS control unit concerning the distance and curve radius covered.
  
• Magnetic field sensor
  The magnetic field sensor is fitted in the rear window shelf and supplies the absolute driving direction.
  
• GPS
  
  The GPS (G lobal P ositioning S ystem) consists of the satellite antenna incorporated in the rear window shelf and the GPS receiver which evaluates the signals received by the antenna and calculates the current position.
  Reception can be interrupted temporarily by shadows in the direct link between satellites and vehicle caused by large buildings or natural obstructions (multi-story buildings, trees etc.).
  The following information is provided on the GPS logo (black square at top right edge of map):
  Apart from the globe, the display field is black.
  Currently no signal is received from any satellite (e.g. possible in workshops). If this situation occurs more frequently and also in areas, in which, based on existing building structures, satellite reception should be possible,then this indicates a fault. Carry out troubleshooting in diagnosis program with symptom "GPS problems".
  Small white dots visible in display field next to globe:
  The number of white dots corresponds to the number of satellites from which signals are received. However, the number of satellites is too low or the position of the satellites is unfavorable such that the current position cannot be calculated.
  A green satellite symbol is shown above the globe in the display field with "GPS" indicated below it. A sufficient number of satellite signals is received in order to determine the position exactly.
  
• Reverse signal
  The navigation computer receives the "reverse" signal via the output of the light module for the right-hand back-up light. This is required in order to determine whether the distance is covered by driving in forward direction or in reverse.
  
• Rear window heating (defroster)
  Since the magnetic field generated by the rear window heating influences the measurements of the magnetic field sensor, the information "rear window defroster ON" is supplied to the navigation computer in order to compensate for the interfering variable.
  

Note

To start the troubleshooting procedure, select Point 1 "Restart diagnosis" following the identification page. In the case of fault symptoms related to positioning errors, a sensor test involving a precisely defined test drive is required in the majority of cases (refer to calibration run for detailed description and prerequisites). This is indicated on the DIS after entering the fault symptoms. The vehicle is disconnected from the DIS in order to carry out the sensor test. Once the sensor test has been completed successfully, continue troubleshooting by selecting Point 2 "Sensor test completed, continue diagnosis" after the identification page.