Navigation/Telecommunication - (Service Information) - 500E: Operation: Navigation

The optional navigation system (also known as Blue&Me™ Maps) provides a dedicated auxiliary port, mounting cradle and charging station for supporting a TomTom® Personal Navigation Device (PND) to the vehicle. The TomTom® PND with its mounting cradle, is docked to a receptacle on the top of the instrument panel just inboard of the Instrument Cluster (IC) (also known as the Instrument Panel Cluster/IPC). The auxiliary port supplies power and ground for charging the TomTom® through the cradle. Communication between the TomTom® and CTM is performed via Bluetooth™. The vehicle operator is guided to the selected destination by voice messages that are broadcast through the speakers, and visual directions on the TomTom® PND electronic display.

Once a destination is selected, the TomTom® PND uses information from stored map data to quickly calculate a route. As the vehicle is driven along that route, the vehicle operator is guided with visual displays and voice prompts. Any variances from that route will cause the TomTom® PND to automatically recalculate and deliver a revised route to the chosen destination. The menu, map or route that was active when the TomTom® PND electronic display was powered Off along with all other user-relevant information is saved in nonvolatile memory by the PND for display again the next time the TomTom® PND electronic display is powered On.

The Global Positioning System (GPS) receiver of the TomTom® PND is capable of acquiring and tracking GPS signal inputs through an integral antenna from numerous satellites simultaneously to calculate and display the position and direction of the vehicle. However, when access to satellite signals is blocked by bridges, tunnels or other obstacles, the PND relies upon Dead Reckoning (DR) to aid in calculating vehicle position and direction. The TomTom® PND uses inputs received through the CTM from other on-board vehicle systems and an internal electronic gyroscope sensor to provide DR vehicle position and direction calculations to supplement GPS satellite signals.

User input mechanisms for the navigation system include the TomTom® PND touchscreen and the Bluetooth™ Hands-Free Voice Recognition (VR) (also known as Voice Command) verbal commands. The VR function uses Advanced Speech Recognition (ASR) software. Master control of the VR function is handled by the VR engine internal and integral to the CTM. The VR recognizes and responds to certain global commands, while other commands are specific to the CTM or the TomTom® PND.

For safety reasons some input, editing and setting features of the navigation system are restricted when the vehicle is in motion or when a hands-free phone call is active. This includes many features that require touchscreen inputs. However, many of those same features disabled for touchscreen inputs remain enabled for Bluetooth™ Hands-Free VR inputs.

The CTM receives electronic message inputs over the Controller Area Network (CAN) - B and the CAN-C data bus; however, the CTM is not a CAN gateway. All electronic message outputs of the CTM are carried over the CAN-B data bus. When the CTM monitors a problem in any of the audio system circuits and components, it stores a fault code or Diagnostic Trouble Code (DTC) in its memory circuit.

The hard wired circuits between components related to the auxiliary port and the charging station may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate System Wiring Diagrams information. The wiring information includes wiring diagrams, proper wire and connector repair procedures, details of wire harness routing and retention, connector pin out information and location views for the various wire harness connectors, splices and grounds.

However, conventional diagnostic methods will not prove conclusive in the diagnosis of the CTM or the electronic controls and communication between modules and other devices that provide some features of the navigation system. The most reliable, efficient and accurate means to diagnose the CTM or the electronic controls and communication related to navigation system operation requires the use of a diagnostic scan tool. Refer to the appropriate Diagnostic information.