
READ GPS DATA
The common misconception made by service personnel when diagnosing navigation system performance
is to s us pect s atellite r ec eption as the c aus e of the f ault. In r eality, the GPS data sensed by the computer is
only processed every few seconds to confirm that the position calculated by the map matching software
process is c orr ec t. Good G PS data is es sential to the s ystem when it is f irs t ins talled in the vehic le, or when
the vehicle is moved from one location to another without the navigation system being active.
W ithin the SATNAV computer unit, there is a separate GPS receiver, which receives the GPS signal from
the antenna and passes calculated inf orm ation to the SAT NAV com puter ’s proc essor . If it is concluded that
the GPS receiver is faulty, the SATNAV computer must be replaced.
RECEIVER STATE DESCRIPTION COMMENT
3D POSITION 3D data on the location
of the vehicle is available
when four or more
satellites are received by
the system.
In this condition, the satellite icon on the guidance screen is
GREEN. This is the normal condition.
2D POSITION 2D data on the location
of the vehicle is available
when three or more
satellites are received by
the system.
No geographic height can be determined in this mode.
Positional accuracy is reduced.
The satellite icon on the guidance screen is RED. This is not the
normal condition, but indicates poor or reduced reception.
TRACKING The data from one
satellite has been
received by the system.
This condition is normally encountered when the system is first
powered up. The GPS receiver will be in this mode for up to 10
minutes depending upon reception conditions.
The satellite icon on the guidance screen is RED.
SEARCH SAT The system has a val id
almanac and is
searching for satellites.
This condition is normally encountered when the system is first
powered up. The GPS receiver will be in this mode for up to 10
minutes depending upon reception conditions.
The satellite icon on the guidance screen is RED.
REC ERROR The system does not
receive the signals. This condition usually occurs if the GPS antenna is not
connected or the cable is damaged. A failed GPS receiver could
be the condition.
The satellite icon on the guidance screen is RED.
COM ERROR The GPS receiver is not
providing any data to the
SATNAV computer’s
processor.
Internal communication between the GPS receiver and the
SATNAV computer is not possible.
READ ERROR MEMORY
The self-diagnosis function of the computer stores
error events to its internal memory. The errors
detected may be due to internal (computer) or
external (environmental or vehicle) conditions. You
may need to view this screen when asked by a
VDO tec hnical consultant during the cour se of fault
diagnosis.
Figure 4K-40
MENU ITEM DESCRIPTION COMMENT
ERROR CODE Lists the errors that have
occurred. Scroll through the errors using the < and > buttons. Press OK
when each error is highlighted to see a description of the error.
ERROR FREQUENCY The number of times the
error has occurred.
SW Software error.
HW Hardware error.
SENSOR No VSS signal.
TEMP Temperature extreme has caused
system error.
GPS Lack of satellite signal.
ERROR TYPE Shows the error type.
NO FAILURE No errors have occurred.