Navigation System: Description and Operation
SYSTEM DESCRIPTION1. DIAGNOSIS DISPLAY DETAILED DESCRIPTION (SYSTEM CHECK)
HINT:
- This contains a detailed description of the displays of the diagnostic mode.
- Illustrations may differ from the actual vehicle depending on the device settings and options. Therefore, some detailed areas may not be exactly the same as on the actual vehicle.
a. System Check Mode Display
1. Device Names and Hardware Address/*1
HINT:
- Registered device names are displayed.
- If a device name is unknown to the system, its physical address is shown instead.
2. Check Result /*2
HINT: Result codes for all devices are shown.
3. Code Clear/*3
Present DTCs are cleared.
4. Memory Clear/*4
Present and past DTCs and registered connected device names are cleared.
b. Diagnosis Menu Display
HINT: Each item is grayed out or not displayed based on the device settings.
c. Unit Check Mode Screen
d. LAN Monitor (Original) Screen
HINT: Check results of all the devices are displayed.
e. LAN Monitor (Individual) Screen
2. DIAGNOSIS DISPLAY DETAILED DESCRIPTION (DISPLAY CHECK)
a. Vehicle Signal Check Mode Screen
HINT:
- Only items sending a vehicle signal will be displayed.
- This screen is updated once per second when input signals to the vehicle are changed.
3. DIAGNOSIS DISPLAY DETAILED DESCRIPTION (NAVIGATION CHECK)
a. Navigation Check MENU Screen
HINT: Each item is grayed out or not displayed based on the device settings.
b. GPS Information Screen
1. Satellite information/*1
Information from a maximum of 12 satellites is displayed on the screen. This information includes the target GPS satellite number, elevation angle, direction and signal level.
2. Receiving condition/*2
3. Measurement information/*3
4. Position information/*4
5. Data information/*5
c. Vehicle Signal Check Screen
HINT: Signals are updated once per second only when vehicle sensor signals are changed.
d. Parts Information Screen
e. Memory Copy / Paste Screen
HINT:
-This function cannot be used on some vehicles.
- When using this function, perform the "Color Bar Check" and "Microphone Check".
- "Color Bar Check".
- "Microphone Check".
4. NAVIGATION SYSTEM OUTLINE
a. Vehicle position tracking methods.
1. It is essential that the navigation system correctly tracks the current vehicle position and displays it on the map. There are 2 methods to track the current vehicle position: autonomous (dead reckoning) and GPS (satellite) navigation. Both tracking methods are used in conjunction with each other.
HINT:
- GPS (Global Positioning System)
- The combination of autonomous and GPS navigation makes it possible to display the vehicle position even when the vehicle is in a place where GPS radio waves cannot be received. When only autonomous navigation is used, however, the mapping accuracy may slightly decline
b. Autonomous navigation
This method determines the relative vehicle position based on the running track determined by the gyro and vehicle speed sensors located in the navigation ECU.
1. Gyro sensor
Calculates the direction by detecting angular velocity. It is located in the radio and navigation assembly.
2. Vehicle speed sensor
Used to calculate the vehicle running distance.
c. GPS navigation (Satellite navigation)
This method detects the absolute vehicle position using GPS radio waves.
HINT: GPS satellites were launched by the U.S. Department of Defense for military purposes.
d. Map matching
The current driving route is calculated by autonomous navigation (according to the gyro sensor and vehicle speed sensor) and GPS navigation. This information is then compared with possible road shapes from the map data in the map disc and the vehicle position is set onto the most appropriate road.
5. DVD (DIGITAL VERSATILE DISC) PLAYER OUTLINE (FOR NAVIGATION MAP)
a. The navigation ECU uses a laser pickup to read the digital signals recorded on a DVD.
CAUTION: Because the navigation system uses an invisible laser beam, do not look directly at the laser pickup. Be sure to only operate the navigation as instructed.
HINT:
- Do not disassemble any part of the navigation ECU.
- Do not apply oil to the navigation ECU.
- Do not insert anything but DVDs into the navigation ECU.
6. MULTI-DISPLAY OUTLINE
a. Touch switch
Touch switches are touch-sensitive (interactive) switches operated by touching the screen. When a switch is pressed, the outer glass bends in to contact the inner glass at the pressed position. By doing this, the voltage ratio is measured and the pressed position is detected.
7. AVC-LAN DESCRIPTION
a. What is AVC-LAN?
AVC-LAN, an abbreviation for "Audio Visual Communication Local Area Network", is a united standard developed by the manufacturers in affiliation with Toyota Motor Corporation. This standard pertains to audio and visual signals as well as switch and communication signals.
b. Purpose:
Recently, car audio systems have rapidly developed and the functions have vastly changed. The conventional car audio system is being integrated with a multimedia interface similar to those in navigation systems. At the same time, customers are demanding higher quality from their audio systems. This is an overview of the AVC-LAN standardization. Its specific purposes are as follows:
1. To solve sound problems, etc., caused by using components of different manufacturers through signal standardization.
2. To allow each manufacturer to concentrate on developing products they do best. From this, reasonably priced products can be produced.
HINT:
- If a +B or GND short is detected in the AVCLAN circuit, communication is interrupted and the audio system will stop functioning.
- If an audio system is equipped with a navigation system, the multi-display unit acts as the master unit. If a navigation system is not equipped, the audio head unit acts as the master unit instead.
- The radio receiver assembly provides resistance to make communication possible.
- A car audio system with an AVC-LAN circuit has a diagnostic function.
- Each component has a specified number (3-digit) called a physical address. Each function has a number (2-digit) called a logical address.
- Components of the navigation system communicate with each other via the AVCLAN.
8. BLUE TOOTH ONLINE
a. BLUETOOTH is a wireless connection technology that uses the 2.4 GHz frequency band. This makes it possible to remotely connect a cellular phone (BLUETOOTH-capable phone) to the multi-display (BLUETOOTH system is built-in), and use a hands free function with the cellular phone even when it is in your pocket or bag.
HINT: Some versions of BLUETOOTH may vary depending on obstructions or radio wave conditions between communication devices, electromagnetic radiation, communication device sensitivity, or antenna capacity.
9. SYSTEM NORMAL CONDITION CHECK
a. If a symptom is applicable to any of the given, it is not a malfunction.
b. The given symptoms are not a malfunction, but are caused by errors inherent in the GPS, gyro sensor, speed sensor, and navigation ECU.
1. The current position mark may be displayed on a nearby parallel road.
2. Immediately after a fork in the road, the current vehicle position mark may be displayed on the wrong road.
3. When the vehicle turns right or left at an intersection, the current vehicle position mark may be displayed on a nearby parallel road.
4. When the vehicle is transported, such as on a ferry, and the vehicle itself is not running, the current vehicle position mark may be displayed in the position where the vehicle was until a measurement is performed by the GPS.
5. When the vehicle runs on a steep hill, the current vehicle position mark may deviate from the correct position.
6. When the vehicle makes a continuous turn of 360 degrees, 720 degrees, 1,080 degrees, etc., the current vehicle position mark may deviate from the correct position.
7. When the vehicle moves erratically, such as during constant lane changes, the current vehicle position mark may deviate from the correct position.
8. When the engine switch is turned on (ACC) / off while on a turntable before parking, the current vehicle position mark may not point in the correct direction. The same will occur when the vehicle comes out of parking.
9. When the vehicle is driven on a snowy road or mountain path with chains installed or a spare tire installed, the current vehicle position mark may deviate from the correct position.
10. When a tire is changed, the current vehicle position mark may deviate from the correct position.
HINT:
- The diameter of the tire may change, causing a speed sensor error.
- Performing the "tire change" in calibration mode will allow the system to correct the current vehicle position faster.