Page 2361 of 4323
DIDBO±01
± DIAGNOSTICSNAVIGATION SYSTEM
DI±2159
2353 Author: Date:
2005 SEQUOIA (RM1146U)
NAVIGATION SYSTEM
PRECAUTION
NOTICE:
When disconnecting the battery terminal, initialize the following system after the terminal is recon-
nected.
System NameSee Page
Back Door Power Window Control SystemBE±77
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DIDBP±01
I27727
Instrument Panel J/B
RAD NO. 2 Fuse
ECU±B Fuse
AM1 FuseEngine Room J/B
RAD NO. 1 Fuse
RAD NO. 3 Fuse
Steering Pad
Switch
Ignition SwitchDisc Player
Controller
(*1)
Stereo
Component
Amplifier
Multi±display
Controller (*1)
VTR
Terminal
(*1)Headphone
Terminal
(*1) (*2)
Radio and
Navigation Assy GPS Antenna
TweeterTelevision Display Assy (*1)
Rear Seat Audio
Controller Assy (*2)
Rear Door SpeakerRear Door Speaker
Front Door Speaker
and Woofer
Front Door Speaker
and Woofer
*1: w/ RSE System
*2: w/ RSA System
DI±2160
± DIAGNOSTICSNAVIGATION SYSTEM
2354 Author: Date:
2005 SEQUOIA (RM1146U)
LOCATION
Page 2363 of 4323
DIDBQ±01
I28761
Radio
and
Navigation
Assy Steering Pad Switch
Stereo
Component
Amplifier
AssyVehicle Speed Signal
Reverse Signal
GPS Antenna
AVC±LAN Park/Neutral Position Switch Combination Meter
Speakers
Display Signal Sound SignalMulti±display
Controller
Assy (*1)
Rear Seat
Audio
Controller
(*2) *1: w/ RSE System
*2: w/ RSA System(*1)
± DIAGNOSTICSNAVIGATION SYSTEM
DI±2161
2355 Author: Date:
2005 SEQUOIA (RM1146U)
SYSTEM DIAGRAM
Page 2364 of 4323

DIDBR±01
I28195
I28196
I28197
DI±2162
± DIAGNOSTICSNAVIGATION SYSTEM
2356 Author: Date:
2005 SEQUOIA (RM1146U)
SYSTEM DESCRIPTION
1. SYSTEM NORMAL CONDITION CHECK
(a) If the symptom is applicable to any of the following, it is intended behavior, and not a malfunction.
SymptomAnswer
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 actu-
al 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.
(b) The following 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 ve-
hicle position mark may be displayed on the wrong
road.
(3) When the vehicle turns right or left at an intersec-
tion, the current vehicle position mark may be dis-
played on a nearby parallel road.
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I28198
I28199
I28200
I28201
I28202
± DIAGNOSTICSNAVIGATION SYSTEM
DI±2163
2357 Author: Date:
2005 SEQUOIA (RM1146U)
(4) 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.
(5) When the vehicle runs on a steep hill, the current ve-
hicle position mark may deviate from the correct
position.
(6) When the vehicle makes a continuous turn of 360,
720, 1,080, etc. degrees, the current vehicle posi-
tion mark may deviate from the correct position.
(7) When the vehicle moves erratically, such as
constant lane changes, the current vehicle position
mark may deviate from the correct position.
(8) 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.
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I28203
I28204
I28187
Radio and Display Assy
Navigation ECURadio and Navigation Assy DI±2164
± DIAGNOSTICSNAVIGATION SYSTEM
2358 Author: Date:
2005 SEQUOIA (RM1146U)
(9) 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.
(10) 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 ºtire changeº 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 ºradio and display assyº and a ºnavigation ECUº are used. This model
has adopted a new type, combining these devices into a single unit.
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I28188
GPS satellite
Navigation
Gyro Sensor
ECU GPS Antenna
Receive satellite
radio waveGPS correction
Create the current
vehicle position
tracking data
Navigation screen
Map disc Map matching
correction Detect direction
change Detect vehicle
running distance
Radio and Navigation Assy
Detect the
measurement position
Map scrolling
Map scale switching Map and current vehicle
position data processing Vehicle Speed Sensor
GPS Antenna
Vehicle Speed SensorLocation by
GPS navigation
Gyro Sensor
Location by
autonomous navigation
± DIAGNOSTICSNAVIGATION SYSTEM
DI±2165
2359 Author: Date:
2005 SEQUOIA (RM1146U)
3. Navigation system outline
(a) 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)
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I28189
Navigation performed even where the
GPS radio wave does not reach.
In a tunnel
In an indoor parking lot
Between tall buildings
Under an overpass
On a forest or tree±lined path
Autonomous navigation
Autonomous navigation and
GPS navigationGPS satellite DI±2166
± DIAGNOSTICSNAVIGATION SYSTEM
2360 Author: Date:
2005 SEQUOIA (RM1146U)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 processingThe navigation ECU displays the vehicle track on the map by processing the ve-
hicle position data, vehicle running track, and map data from the map disc.
Map MatchingThe 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 mea-
surement 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 off-
sets 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.