PRECAUTION Toyota Sequoia I facelift

PRECAUTION

Note. When disconnecting the battery terminal, initialize the following system after the terminal is reconnected.

NAVIGATION SYSTEM REFERENCE CHART

Scheme 144

Scheme 145

Scheme 146

Scheme 147

Scheme 148

Scheme 149

Scheme 150

Scheme 151

Scheme 152

Scheme 153

Scheme 154

Scheme 155

Scheme 156

Scheme 157

Scheme 158

Scheme 159

Scheme 160

Scheme 161

Scheme 162

1. SYSTEM NORMAL CONDITION CHECK If the symptom is applicable to any of the following, it is intended behavior, and not a malfunction. SYSTEM NORMAL CONDITION CHECK Symptom Answer A longer route than expected is chosen. Depending on the road conditions, the navigation ECU may determine that a longer route is quicker. Even when distance priority is high, the shortest route is not shown. Some paths may not be advised due to safety concerns. When the vehicle is put into motion immediately after the engine starts, the navigation system deviates from the actual position. If the vehicle starts before the navigation system activates, the system may not react. When running on certain types of roads, especially new roads, the vehicle position deviates from the actual position. When the vehicle is driving on new roads not available on the map disc, the system attempts to match it to another nearby road, causing the position mark to deviate. The following symptoms are not a malfunction, but are caused by errors inherent in the GPS, gyro sensor, speed sensor, and navigation ECU. The current position mark may be displayed on a nearby parallel road. Immediately after a fork in the road, the current vehicle position mark may be displayed on the wrong road. When the vehicle turns right or left at an intersection, the current vehicle position mark may be displayed on a nearby parallel road. When the vehicle is carried, 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 can be performed by GPS. When the vehicle runs on a steep hill, the current vehicle position mark may deviate from the correct position. When the vehicle makes a continuous turn of 360, 720, 1,080, etc. degrees, the current vehicle position mark may deviate from the correct position. When the vehicle moves erratically, such as constant lane changes, the current vehicle position mark may deviate from the correct position. When the ignition switch is turned to the ACC or ON position 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. When the vehicle runs on the snowy road or a mountain path with the chains installed or using a spare tire, the current vehicle position mark may deviate from the correct position. When a tire is changed, the current vehicle position mark may deviate from the correct position. HINT: 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.
2. Radio and navigation assy outline Conventionally, 2 separate devices, a "radio and display assy" and a "navigation ECU" are used. This model has adopted a new type, combining these devices into a single unit.
3. Navigation system outline Vehicle position tracking methods 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 navigation methods are used in conjunction with each other. *GPS (Global Positioning System) NAVIGATION SYSTEM DESCRIPTION Operation Description Vehicle Position Calculation The navigation ECU calculates the current vehicle position (direction and current position) using the direction deviation signal from the gyro sensor and the running distance signal from the vehicle speed sensor and creates the driving route. Map Display processing The navigation ECU displays the vehicle track on the map by processing the vehicle position data, vehicle running track, and map data from the map disc. Map Matching The map data from the map disc is compared to the vehicle position and running track data. Then, the vehicle position is matched with the nearest road. GPS Correction The vehicle position is matched to the position measured by GPS. Then, the measurement position data from the GPS unit is compared with the vehicle position and running track data. If the position is widely different, the GPS measurement position is used. Distance Correction The running distance signal from the vehicle speed sensor includes the error caused by tire wear and slippage between the tires and road surface. Distance correction is performed to account for this. The navigation ECU automatically offsets the running distance signal to make up for the difference between it and the distance data of the map. The offset is automatically updated. HINT: The combination of autonomous and GPS navigation makes it possible to display the vehicle position even when the vehicle is in places where the GPS radio wave cannot receive a signal. When only autonomous navigation is used, however, the mapping accuracy may slightly decline. 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. Gyro sensor Calculates the direction by detecting angular velocity. It is located in the radio and navigation assy. Vehicle speed sensor Used to calculate the vehicle running distance. GPS navigation (Satellite navigation) This method detects the absolute vehicle position using radio wave from a GPS satellite. * GPS satellites were launched by the U.S. Department of Defence for military purposes. GPS NAVIGATION REFERENCE CHART Number of satellites Measurement Description 2 or less Measurement impossible Vehicle position cannot be obtained because the number of satellites is not enough. 3 2-dimensional measurement is possible Vehicle position is obtained based on the current longitude and latitude (This is less precise than 3-dimensional measurement). 4 3-dimensional measurement is possible Vehicle position is obtained based on the current longitude, latitude and altitude. 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. 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.
4. DVD (Digital Versatile Disc) player outline (for Navigation Map) The navigation ECU uses a laser pickup to read the digital signals recorded on a DVD. HINT: Do not disassemble any part of the navigation system. Do not apply oil to the navigation system. Do not insert anything but a DVD into the navigation system. 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.
5. CD (Compact Disc) Player Outline A CD player uses a laser pickup to read digital signals recorded on a CD. By converting the digital signals to analog, it can play music and other things. In general, CD players can play a 4.7-inch (12 cm) or 3.2-inch (8 cm) disc. HINT: Do not disassemble any part of the CD player. Do not apply oil to the CD player. Do not insert anything but a CD into the CD player. CAUTION: Because the CD player uses an invisible laser beam, do not look directly at the laser pickup. Be sure to only operate the player as instructed.
6. AVC-LAN Description 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. Purpose: Recently, car audio systems have rapidly developed and the functions vastly changed. The conventional car audio system is being integrated with multi-media interfaces similar to those in navigation systems. At the same time, customers are demanding higher quality from their audio systems. This is merely an overview of the standardization background. The specific purposes are as follows. To solve sound problems, etc. caused by using components of different manufacturers through signal standardization. To allow each manufacturer to concentrate on developing products they do best. From this, reasonably priced products can be produced. HINT: If a short to +B or short to ground is detected in the AVC-LAN 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 the navigation system is not equipped, the audio head unit acts as the master unit instead. If the radio and navigation assy is equipped, it is the master unit. The radio and navigation assy provides resistance to make communication possible. The 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.
7. Communication System outline Components of the audio system communicate with each other via the AVC-LAN. The master component of the AVC-LAN is a radio and navigation assy with a 60 to 80 ohm resistor. This is essential for communication. If a short circuit or open circuit occurs in the AVC-LAN circuit, communication is interrupted and the audio system will stop functioning.
8. Diagnostic function outline The audio system has a diagnostic function (the result is indicated on the master unit). A 3-digit hexadecimal component code (physical address) is allocated to each component on the AVC-LAN. Using this code, the component in the diagnostic function can be displayed.

Scheme 163

Scheme 164

Scheme 165

Scheme 166

Scheme 167

Scheme 168

Scheme 169

1. Radio frequency band Radio Broadcasts use the radio frequency bands shown in the table below. LF: Low Frequency MF: Medium Frequency HF: High Frequency VHF: Very High Frequency
2. Service area The service areas of the AM and FM broadcasts are vastly different. Even if an AM broadcast has clear reception, an FM broadcast originating in the same location may not be received at all. The service area of FM stereo broadcasts is small, and static as well as interference (noise) easily enters the signal.
3. Radio reception problems HINT: In addition to static, other problems such as "phasing", "multi-path", and "fade out" exist. These problems are not caused by electrical noise, but by the radio signal propagation method itself. Phasing The AM frequency band reflects off the earth's ionosphere at night. When this occurs, the reflected signal may interfere with the direct signal sent by the same transmitter. This phenomenon is known as "phasing". Multi-path A radio signal can sometimes be reflected by an obstruction in its path. When this occurs, the reflected signal may interfere with the direct signal sent from the transmitter. This phenomenon is known as "Multi-path". Fade out FM radio frequency is higher than AM. Therefore, it is more likely to be reflected by large obstructions such as tall buildings or mountains. For this reason, the FM signal will gradually weaken or disappear when the vehicle is behind such obstructions. This phenomenon is known as "fade out".
4. Noise problem It is very important for a technician to understand the specifics of the noise problem. To diagnose the symptom, use the table below. NOISE PROBLEM SYMPTOM CHART Radio Frequency Noise occurrence condition Presumable cause AM Noise occurs in a specified area Foreign noise AM Noise occurs when listening to an intermittent broadcast An identical program transmitted from multiple towers can cause noise where the signals overlap AM Noise occurs only at night Music beat from a far-off broadcast FM Noise occurs while driving in a specified area Multi-path or phasing noise resulting from a change in FM frequency HINT: If the noise does not fall into any category in the table above, determine the cause using "Radio reception problems" above. Refer to the multi-path and phasing sections.