Principles of Operation (How Does It Work?)
PRINCIPLES OF OPERATIONNavigation System
The navigation system module controls the operation and the interface between the user, the vehicle subsystems and the external components. The navigation system module is on the standard corporate protocol (SCP) network and can be diagnosed with a diagnostic tool. Communication through the controller area network (CAN) utilizes data transmitted and received between the navigation system module and the audio unit to control the video screen display through the video interface circuits.
The vehicle navigation system will guide the user to a pre-entered destination. A map DVD stored in the navigation system module sends route calculation data to the audio unit. The system will audibly and visually instruct the user of the maneuvers required to arrive at the destination entered.
A voice recognition system allows user to interface with the system without using the touch screen. A microphone located in the rear view mirror provides a direct input to the navigation system module.
In order to calculate the initial vehicle position, the GPS antenna is used to track several available satellites simultaneously. The GPS antenna only receives data and does not communicate with the satellites. A gyroscope integral to the navigation system module monitors the pitch and yaw of the vehicle created during cornering or turning. A hardwired vehicle speed input from the powertrain control module (PCM) and a reverse input from the digital transmission range (TR) sensor are also used to detect vehicle speed and direction changes.
Self Diagnostics
Although on the SCP network, the navigation system provides internal diagnostics to assist with diagnosing vehicle concerns.
Press and hold the AUDIO and MENU buttons for 5 seconds.
Press 917 Enter.
- SELF CHECK provides internal self-test diagnostics. These DTCs are also accessible through the SCP network utilizing a diagnostic tool.
- NAVIGATION INFO provides access to speed signal, gyro, reverse input, and GPS information.
- SUB-SYSTEM INFO provides the various component configurations.
- MANUAL CHECK provides access to several diagnostics input tests:
- Voice Output will verify the audio signals from the navigation system module and audio unit.
- Hard Switch Test will check the various hardkey switches.
- Microphone Test will check the strength of the voice signal.