Abstract: A route guidance section compares the current position provided by a current position determination section and the route provided by a route calculation section for detecting an off-route condition. When the off-route condition is detected, a re-searching key as well as the route and current place is displayed on a display section. When the re-searching key is touched, a search is again made for a new route from the current position to the destination. Then, route guidance is again started in response to the re-searching result. When the re-searching key is not touched, the route and current place continue to be displayed while the vehicle carrying the apparatus travles off route, thereby efficiently preventing the apparatus from executing unnecessary re-searching when the driver drives the vehicle off route on purpose.

Abstract: In a vehicle control system having a main electronic control unit governing a plurality of subsidiary electronic control units, each of the subsidiary units includes an automatic continuous subsidiary unit self-diagnosis procedure which generates an interrupt signal causing the main electronic control unit to retrieve date and time data from the main unit clock. This subsidiary malfunction date and time data along with details of the subsidiary unit malfunction can be stored in either the main unit memory or the respective subsidiary unit memory for subsequent retrieval and display by an operator via the main control unit. Any malfunction of the main electronic control unit is similarly detected, stored and output by the main control unit for display.

Abstract: A route guidance section compares the current position provided by a current position determination section and the route provided by a route calculation section for detecting an off-route condition. When the off-route condition is detected, a researching key as well as the route and current place is displayed on a display section. When the researching key is touched, a search is again made for a new route from the current position to the destination. Then, route guidance is again started in response to the researching result. When the researching key is not touched, the route and current place continue to be displayed while the vehicle carrying the apparatus travles off route, thereby efficiently preventing the apparatus from executing unnecessary researching when the driver drives the vehicle off route on purpose.

Abstract: In a vehicle navigation system, when a voice control part, which is displayed on a screen, is switched off, a voice control part inhibits voice guidance from being output to a speaker. Now, if a current-location/guide selection key is operated, the voice control part creates voice guidance according to the operation of the selection key and outputs the voice guidance from the speaker. With this navigation system, aural route guidance is possible only at the driver's request.

Abstract: A vehicle route guidance system includes a map information storage section 10 which has a road type storage section 10a for storing various types of roads such as toll roads, express highways and motorways. A route guidance control section 26 reads out map information including road type information and route information. A road type change point detecting section 26a detects a road type change point. The route guidance control section 26 causes a display 28 and a voice controller 30 to perform the route guidance when a vehicle approaches a point a given distance short of the road type change point. The voice controller 30 responds to the instruction from the route guidance control section 26 to announce the route guidance for informing the driver of the entry to a toll road, express highway or motorway.

Abstract: In a vehicle navigation system, when a voice control part, which is displayed on a screen, is switched off, a voice control part inhibits voice guidance from being output to a speaker. Now, if a current-location/guide selection key is operated, the voice control part creates voice guidance according to the operation of the selection key and outputs the voice guidance from the speaker. With this navigation system, aural route guiding is possible only at the driver's request.