Principles of Operation

The vehicle navigation system provides a feature that will guide the user to a pre-entered destination. The system uses the Global Positioning Sensor (GPS), vehicle speed, and other sensor information to accurately establish vehicle position. The Navigation System Module (NSM) sends information to the Navigation System Display Module (NSDM) and compares this position to the CD-ROM vector map. The system then instructs the user of the maneuvers required during the journey in order to arrive at the destination entered.

The major components of the vehicle navigation system are:
^ Global Positioning Sensor (GPS) antenna
^ Navigation system display module (NSDM)
^ Navigation system module (NSM)
^ Navigation system console harness
^ Navigation system Compact Disc (CD)
^ Navigation GPS antenna cable in instrument panel

The GPS antenna is used to initially find the global location. The system tracks different satellites simultaneously, when available, in order to calculate the position. The GPS only receives data and does not communicate back to the satellites.

A gyroscopic device along with vehicle speed input from the Powertrain Control Module (PCM) is used to improve the accuracy of the navigation system. The gyroscope monitors the turning forces created when the vehicle is cornering and detects changes in direction. A reverse input from the Rear Electronic Module (REM), is also required by the NSM to indicate direction.

The NSM will only function with the ignition switch is in the RUN or ACC position. The NSM utilizes internal self-test diagnostics, and is not compatible with a scan tool.







READ ERROR MEMORY
^ ERROR CODE will indicate a four digit DTC if a fault is detected. If no fault is detected the system will indicate NO FAILURE.
^ NO. OF ERRORS.
^ ERROR TYPE.












READ I/O STATE
^ SPEED PULSES indicate the vehicle rate of travel in pulses. The pulse will be approximately double the reading of the speedometer.
^ TEMPERATURE is an indication of the inside temperature of the NSM.
^ BATTERY indicates the power supply state to the NSM.
^ EJECT will indicate 0 as normal state and 1 when the eject button is pushed on the navigation system CD player.
^ DIRECTION will indicate FWD or REV as related to the position of the gear selector lever.
^ LIGHT will indicate OFF when the headlamps/parklamps are in the off position and ON when the headlamps/parklamps are switched on.












READ GPS DATA
^ SEARCH SAT. will indicate NO SATELLITE DATA if satellite signal is not received.
^ LONGITUDE will indicate the global location in degrees.
^ LATITUDE will indicate the global location in degrees.
^ GEOGRAPHIC HEIGHT will indicate global position in meters above sea level.
^ NO. OF SATELLITES will indicate the number of satellite signals being retrieved by the NSM. Minimum requirements are two satellite signals with a maximum of eight. Reception from more than three satellites will be displayed as >3.





















Technical Assistance
If there are problems during the diagnosis or it is not clear how to proceed with the repair, call Technical Assistance. BEFORE calling Technical Assistance, the Navigation Function Test must be carried out. The following information is needed to identify the system and software version. This information is available by selecting "Main Menu", "Settings", "System Information", "Configuration". "System Identification" information will appear. Please have this information and a detailed description of the problem. Technical Assistance 1-888-253-5890 (Hours of operation: M-F, 9am to 6pm EST).