TOYOTA SEQUOIA 2001 Service Repair Manual

± DIAGNOSTICSNAVIGATION SYSTEM
DI±2169
2363 Author: Date:
2005 SEQUOIA (RM1146U)
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.

I28687
Main AVC±LAN:
(*1, 2) Multi±display Controller
Sub±assy (*1)
 Rear Seat Audio
Controller (*2) Radio and Navigation Assy Stereo Component
Amplifier Assy
Sub AVC±LAN:
Disc Player
Controller (*1) Television Display Assy (*1)
*1 w/ RSE
*2: w/ RSA
: AVC±LAN DI±2170
± DIAGNOSTICSNAVIGATION SYSTEM
2364 Author: Date:
2005 SEQUOIA (RM1146U)
6. AVC±LAN Description
(a) What is AVC±LAN?
AVC±LAN, an abbreviation for ºAudio Visual Communication Local Area Networkº, 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 vastly changed. The conven-
tional 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.
(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, rea-
sonably priced products can be produced.

± DIAGNOSTICSNAVIGATION SYSTEM
DI±2171
2365 Author: Date:
2005 SEQUOIA (RM1146U)
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 num-
ber (2±digit) called a logical address.
7. Communication system outline
(a) Components of the audio system communicate with each other via the AVC±LAN.
(b) The master component of the AVC±LAN is a radio and navigation assy with a 60 to 80 W resistor. This
is essential for communication.
(c) 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
(a) The audio system has a diagnostic function (the result is indicated on the master unit).
(b) 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.

DIDBS±01
Vehicle brought into a workshop
1. Diagnostic questioning and symptom confirmation
HINT:
Ask the customer about symptoms and confirm malfunctions.
Fill out the Customer Problem Analysis check sheet.
The screen displays nothing (Go to step 5, proceed
to ºBLACK SCREEN (NO IMAGE APPEARS ON
NAVIGATION/AUDIO SCREEN)º) P. DI±2214 Other symptoms
2. Confirm the system normal condition
P. DI±2162Applicable (This is not a malfunction.)
Not applicable
3. Check the diagnostic trouble codes
HINT:

Even if the malfunction symptom is not confirmed, check the diagnostic trouble codes.
This is because the system stores past diagnostic trouble codes.

Refer to the detailed description on the diagnostic screen, as necessary. A code is outputA code is not output (Go to step 5)
4. Diagnostic trouble code chart.
HINT:
Find the output code on the diagnostic trouble code chart.Output the diagnostic trouble code (Go to step 7)
5. Problem symptoms table
HINT:
If the symptom does not recur and no code is output,
perform the symptom reproduction method.There is an applicable symptom code in the table
(Go to step 7)
There is no applicable
symptom code in the
table
6. Check the ECU terminal arrangement based on the malfunction symptom
7. Circuit inspection and part inspection
8. Recheck the diagnostic trouble code
HINT:
After deleting the DTC, recheck the diagnostic trouble code.
9. Perform confirmation test
ENDItems inside
are titles of pages in this manual,
with the page number in the bottom portion. See
the pages for detailed explanations.
P. DI±2191
P. DI±2214 ± DI±2294 P. DI±2203
P. DI±2184
P. DI±2199
DI±2172
± DIAGNOSTICSNAVIGATION SYSTEM
2366 Author: Date:
2005 SEQUOIA (RM1146U)
HOW TO PROCEED WITH TROUBLESHOOTING

DIDBT±01
/ /
/ /
I28194
Inspector 's name:
Customer 's NameVIN
Production Date
Licence Plate No.
Odometer Readingkm
mile
Frequency Problem Occurs
Always
Intermittently ( times a day) Brought in
Date Problem First OccurredDate Vehicle
Problem SymptomDTC Check
1st time trouble code.
2nd time trouble code. RADIO AND NAVIGATION SYSTEM Check Sheet
± DIAGNOSTICSNAVIGATION SYSTEM
DI±2173
2367 Author: Date:
2005 SEQUOIA (RM1146U)
CUSTOMER PROBLEM ANALYSIS CHECK

DIDBU±01
30 kHz 300 kHz 3 MHz 30 MHz 300 MHz
LF MF HF VHF
AM FM
Frequency modulation Frequency
Designation
Radio wave
Modulation Amplitude modulation
BE2818
FM (Stereo)
FM (Monaural)
AM
BE2819
Ionosphere Phasing: DI±2174
± DIAGNOSTICSNAVIGATION SYSTEM
2368 Author: Date:
2005 SEQUOIA (RM1146U)
IDENTIFICATION OF NOISE SOURCE
Radio Description
(a) 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
(b) Service area
The service areas of the AM and FM broadcasts are vast-
ly 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 sig-
nal.
(c) Radio reception problems
HINT:
In addition to static, other problems such as ºphasingº, ºmulti±pathº, and ºfade outº exist. These problems
are not caused by electrical noise, but by the radio signal propagation method itself.
(1) Phasing
The AM frequency band reflects off the earth's iono-
sphere at night. When this occurs, the reflected sig-
nal may interfere with the direct signal sent by the
same transmitter. This phenomenon is known as
ºphasingº.

BE2820
Multi±path:
BE2821
Fade Out:
± DIAGNOSTICSNAVIGATION SYSTEM
DI±2175
2369 Author: Date:
2005 SEQUOIA (RM1146U)
(2) Multi±path
A radio signal can sometimes be reflected by an ob-
struction in its path. When this occurs, the reflected
signal may interfere with the direct signal sent from
the transmitter. This phenomenon is known as ºMul-
ti±pathº.
(3) 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 ºfade outº.
(d) 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.
Radio FrequencyNoise occurrence conditionPresumable cause
AMNoise occurs in a specified areaForeign noise
AMNoise occurs when listening to an intermittent
broadcastAn identical program transmitted from multiple
towers can cause noise where the signals over-
lap
AMNoise occurs only at nightMusic beat from a far±off broadcast
FMNoise occurs while driving in a specified areaMulti±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 ºRadio reception
problemsº above. Refer to the multi±path and phasing sections.

DIDBV±01
I28218
I28219
I28220
DI±2176
± DIAGNOSTICSNAVIGATION SYSTEM
2370 Author: Date:
2005 SEQUOIA (RM1146U)
DISPLAY CHECK MODE (Color Bar Check)
HINT:

This mode checks the color display on the radio and navigation assy.

Illustrations may differ from the actual vehicle depending on the device settings and options. There-
fore, some detailed areas may not be shown exactly the same as on the actual vehicle.
1. Enter diagnostic mode (See page DI±2191).
2. Select ºDisplay Checkº from the ºDiagnosis MENUº
screen.
3. Select ºColor Bar Checkº from the ºDisplay Checkº
screen.
4. Select a color bar from the ºColor Bar Check Modeº
screen.
HINT:

The entire screen turns to the color or stripe selected.

Touching the display will return to the ºColor Bar Checkº
screen.

DIDBW±01
I28218
I28221
I28222
± DIAGNOSTICSNAVIGATION SYSTEM
DI±2177
2371 Author: Date:
2005 SEQUOIA (RM1146U)
DISPLAY CHECK MODE (Touch Switch Check)
HINT:

This mode checks the touch switch operation condition on the radio and navigation assy.

Illustrations may differ from the actual vehicle depending on the device settings and options. There-
fore, some detailed areas may not be shown exactly the same as on the actual vehicle.
1. Enter diagnostic mode (See page DI±2191).
2. Select ºDisplay Checkº from the ºDiagnosis MENUº
screen.
3. Select ºTouch Switch Checkº from the ºDisplay
Checkº screen.
4. Touch the display anywhere in the open area to per-
form the check when the ºTouch Switch Checkº
screen is displayed.
HINT:

A º+º mark is displayed where the display is touched.

The º+º mark remains on the display even after the finger
is removed.

DIDBX±01
I28218
I28223
*1
*2 *3
I28224
DI±2178
± DIAGNOSTICSNAVIGATION SYSTEM
2372 Author: Date:
2005 SEQUOIA (RM1146U)
DISPLAY CHECK MODE (Panel Switch Check)
HINT:

This mode checks the panel switch operation response on the radio and navigation assy.

Illustrations may differ from the actual vehicle depending on the device settings and options. There-
fore, some detailed areas may not be shown exactly the same as on the actual vehicle.
1. Enter diagnostic mode (See page DI±2191).
2. Select ºDisplay Checkº from the ºDiagnosis MENUº
screen.
3. Select ºPanel Switch Checkº from the ºDisplay
Checkº screen.
4. Operate each switch and check that the switch name
and condition are correctly displayed.
HINT:

Pressing the ºDISPLAYº switch for 3 seconds will exit the
diagnostic mode.

ºOPENº and ºTILTº switches are not displayed. To test
these switches, they must be operated.
DisplayContents
Push switch name/*1
Name of the pressed switch is displayed.

If more than one switch is pressed, ºMULTIPLEº is displayed.
Rotary switch name/*2Name of the rotary switch is displayed.
Rotary switch direction/*3Direction of the rotary switch is rotated.