2001 TOYOTA SEQUOIA navigation

IN01T±18
± INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMSIN±23
23 Author: Date:
HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS
GENERAL INFORMATION
A large number of ECU controlled systems are used in the SEQUOIA. In general, the ECU controlled system
is considered to be a very intricate system requiring a high level of technical knowledge and expert skill to
troubleshoot. However, the fact is that if you proceed to inspect the circuits one by one, troubleshooting of
these systems is not complex. If you have adequate understanding of the system and a basic knowledge
of electricity, accurate diagnosis and necessary repair can be performed to locate and fix the problem. This
manual is designed through emphasis of the above standpoint to help service technicians perform accurate
and effective troubleshooting, and is compiled for the following major ECU controlled systems:
The troubleshooting procedure and how to make use of it are described on the following pages.
SystemPage
1. EngineDI±1
2. Automatic TransmissionDI±515
3. Air Suspension Control SystemDI±695
4. Tire Pressure Warning SystemDI±796
5. ABS with EBD & BA & TRAC & VSC SystemDI±891
6. Can Communication SystemDI±1060
7. Supplemental Restraint SystemDI±1118
8. Power Seat Control System w/ Driving Position MemoryDI±1501
9. Cruise Control SystemDI±1536
10.Engine Immobilizer SystemDI±1570
11. Combination Meter SystemDI±1601
12.Sliding Roof SystemDI±1661
13.Body Control SystemDI±1678
14.Driver Door Control SystemDI±1778
15.Passenger Door Control SystemDI±1814
16.Back Door Control SystemDI±1850
17.Multiplex Communication SystemDI±1887
18.Audio SystemDI±1955
19.Rear Seat Audio SystemDI±2044
20.Rear Seat Entertainment SystemDI±2078
21.Navigation SystemDI±2159
22.Air Conditioning SystemDI±2297
FOR USING OBD II SCAN TOOL OR TOYOTA HAND±HELD TESTER

Before using the scan tool or tester, the scan tool's instruction book or tester's operator manual should
be read thoroughly.

If the scan tool or tester cannot communicate with ECU controlled systems when you have connected
the cable of the scan tool or tester to DLC3, turned the ignition switch ON and operated the scan tool,
there is a problem on the vehicle side or tool side.
(1) If communication is normal when the tool is connected to another vehicle, inspect the diagnosis
data link line (Bus
line) or ECU power circuit of the vehicle.
(2) If communication is still not possible when the tool is connected to another vehicle, the problem
is probably in the tool itself, so perform the Self Test procedures outline in the Tester Operator's
Manual.

I28193
AVC±LANStereo Component
Amplifier Assy Radio Receiver Assy
(Resistor 60 to 80 W)
Example : DI±1960
± DIAGNOSTICSAUDIO SYSTEM
2154 Author: Date:
2005 SEQUOIA (RM1146U)
4. OUTLINE OF AVC±LAN
(a) What is AVC±LAN?
AVC±LAN is the abbreviation for Audio Visual Communication±Local Area Network. This is a unified
standard co±developed by 6 audio manufacturers associated with Toyota Motor Corporation.
The unified standard includes signals, such as audio, visual and signals for switch indication and com-
munication.
(b) Objectives
Recently development in car audio systems has been rapid and functions have been changed drasti-
cally. The conventional system has been switched to a multi±media type such as a navigation system.
At the same time customers wants to upgrade their audio systems. This is the factor that lies behind
this standardization.
The concrete objectives are explained below.
(1) When products by different manufacturers were combined together, malfunctions such as sound
failure occurred. This problem can be solved by standardization of signals.
(2) Various types of after market products are available.
(3) In general, a new product developed by a particular manufacturer could not be used due to a
lack of compatibility with other manufacturer's products. By developing this new standard, users
can enjoy a range of compatible products from different manufacturers.
HINT:

When +B short or GND short is detected in the AVC±LAN circuit, communication stops, and the audio
system will not function.

When the audio system is not equipped with a navigation system, the audio head unit is the master
unit. When the audio system is equipped with a navigation system, the multi±display is the master unit.

The radio receiver assy is equipped with a resistor (60 to 80 W) for communication.

All car audio systems using an AVC±LAN circuit have a diagnostic function.

Each unit has its own specified number called a physical address (three±digit number). Numbers are
also allotted to each function, which are called logical addresses (two±digit number).
5. COMMUNICATION SYSTEM
(a) Components in the audio system communicate with each other through the AVC±LAN. (Radio receiver
with CD changer control function)
(b) When a short circuit or circuit breakdown occurs in the AVC±LAN circuit, the audio system does not
operate normally due to the communication cutoff.

DID9Q±01
± DIAGNOSTICSAUDIO SYSTEM
DI±1967
2161 Author: Date:
2005 SEQUOIA (RM1146U)
PROBLEM SYMPTOMS TABLE
NOTICE:
For the troubleshooting procedures of the audio system with a navigation system, refer to the navi-
gation system (See page DI±2184).
RADIO RECEIVER ASSY
HINT:
Inspect the ºFuseº and ºRelayº before confirming the suspected area as shown in the charts below.
SymptomSuspected AreaSee page
Pressing power switch does not start system.3. Power source circuit (radio receiver assy)
4. Radio receiver assyDI±1990
±
A audio system cannot be operated.1. Steering pad switch circuit
2. Radio receiver assyDI±1995
±
No sound cannot be heard (Separate type amplifier).
1. Power source circuit (stereo component amplifier assy)
2. Sound signal circuit
3. Speaker circuit
4. AVC±LAN circuit (radio receiver assy ± stereo compo-
nent amplifier)
5. AVC±LAN circuit (radio receiver assy ± rear seat audio
controller) w/ RSA system
6. AVC±LAN circuit (radio receiver assy ± multi±display
controller) w/ RSE system
7. Mute signal circuit
8. Stereo component amplifier assy
9. Radio receiver assyDI±1993
DI±2011
DI±2013
DI±2023
DI±2061
DI±2139
DI±2008
±
±
No sound cannot heard (Built±in type amplifier).
1. Power source circuit (radio receiver assy)
2. Speaker circuit
3. Radio receiver assyDI±1990
DI±2013
±
Sound quality is bad in all modes (volume is too low).
(Separate type amplifier)
1. Power source circuit (radio receiver assy)
2. Power source circuit (stereo component amplifier assy)
3. Speaker circuit
4. Sound signal circuit
5. Sound quality is bad in all modes (volume is too low)
6. Stereo component amplifier assyDI±1990
DI±1993
DI±2013
DI±2011
DI±2026
±
Sound quality is bad in all modes (volume is too low).
(Built±in type amplifier)1. Power source circuit (radio receiver assy)
2. Speaker circuit
3. Sound quality is bad in all modes (volume is too low)DI±1990
DI±2013
DI±2026
Noise occurs.±DI±2027
Radio broadcast cannot be received (bad reception).±DI±2028
CD cannot be inserted or is ejected right after insertion.1. Power source circuit (radio receiver assy)
2. CD cannot be inserted or is ejected right after insertionDI±1990
DI±2030
CD cannot be ejected.1. Power source circuit (radio receiver assy)
2. CD cannot be ejectedDI±1990
DI±2032
Sound quality is bad only when playing CD (volume is too low).±DI±2033
CD sound skips.±DI±2034
Cassette tape cannot be inserted or played.1. Power source circuit (radio receiver assy)
2. Cassette tape cannot be inserted or playedDI±1990
DI±2036
Cassette tape cannot be ejected.1. Power source circuit (radio receiver assy)
2. Cassette tape cannot be ejectedDI±1990
DI±2038
Sound quality is bad only when playing tape.±DI±2040
Tape is tangled due to incorrect tape speed or auto±reverse mal-
function.±DI±2042

DIDAE±01
I27729
Radio and Navigation Assy (*1)
Radio Receiver Assy (*2)
Rear Door
Speaker Tweeter
Rear Door Speaker Front Door Speaker
and Woofer
Steering Pad Switch Instrument Panel J/B

RAD NO. 2 Fuse

ECU±B

AM1 FuseEngine Room J/B

RAD NO. 1 Fuse

RAD NO. 3 Fuse
Ignition Switch
Rear Seat Audio
Controller Assy
Headphone
Terminal
Front Door
Speaker
and Woofer
Stereo Component
Amplifier
*1: w/ Navigation System
*2: w/o Navigation System
± DIAGNOSTICSREAR SEAT AUDIO SYSTEM
DI±2045
2239 Author: Date:
2005 SEQUOIA (RM1146U)
LOCATION

DIDAF±01
I28753
Sound Signal
Rear Seat Audio Controller Radio Receiver Assy
or
Radio and Navigation
AssyAVC±LAN
Speakers Stereo Component
Amplifier Assy
Switch AssyWireless
HeadphoneHeadphone
Terminal
Wired Headphone Wired Headphone DI±2046
± DIAGNOSTICSREAR SEAT AUDIO SYSTEM
2240 Author: Date:
2005 SEQUOIA (RM1146U)
SYSTEM DIAGRAM

DIDAG±01
I28272
AVC±LAN:
Stereo Component
Amplifier Assy
Radio Receiver Assy
(w/o Navigation)

Radio and Navigation Assy
(w/ Navigation)
Rear Seat Audio Controller
: AVC LAN
± DIAGNOSTICSREAR SEAT AUDIO SYSTEM
DI±2047
2241 Author: Date:
2005 SEQUOIA (RM1146U)
SYSTEM DESCRIPTION
1. OUTLINE
(a) Rear Seat Audio (RSA) system, which consists of a rear seat audio controller and a remote controller
(switch assy), enables the rear seat occupants to use headphones to listen simultaneously to a differ-
ent audio mode than the one that is selected in the front audio head unit.
2. COMMUNICATION SYSTEM

DIDAK±01
DI±2050
± DIAGNOSTICSREAR SEAT AUDIO SYSTEM
2244 Author: Date:
2005 SEQUOIA (RM1146U)
PROBLEM SYMPTOMS TABLE
RSA SYSTEM
SymptomSuspected AreasSee page
RSA system cannot be powered.1. Power source circuit (rear seat controller assy)DI±2058
Quality of sound from wireless headphone is poor or no sound
can be heard.
1. Power source circuit (rear seat controller assy)
2. Mute signal circuit (to rear seat audio controller)
3. Sound signal circuit (to rear seat audio controller)
4. Rear seat audio controllerDI±2058
DI±2066
DI±2070
±
Quality of sound from headphone connected to headphone termi-
nal is poor or no sound can be heard.
1. Power source circuit (rear seat controller assy)
2. Mute signal circuit (to rear seat audio controller)
3. Sound signal circuit (Rear seat audio controller ± head-
phone terminal)
4. Sound signal circuit (Radio receiver assy / radio and
navigation assy ± rear seat audio controller)DI±2058
DI±2066
DI±2073
DI±2070
REMOTE CONTROL
SymptomSuspected AreasSee page
A remote control system does not operate.
1. Power source circuit (rear seat controller assy)
2. A remote control system does not operate
3. AVC±LAN circuitDI±2058
DI±2076
DI±2061

I28599I28773
w/o Navigation:
Radio Receiver Assy
Rear Seat Audio Controller
R19
Stereo Component Amplifier AssyTX± TX+
S10 ID2
LG
LG
V
P L 9
10
5
R41522
R24
23
TX1± TX1+
TX± TX+27 26
TX± TX+ 20
19 R19
R4LGID2 R24
S10
± DIAGNOSTICSREAR SEAT AUDIO SYSTEM
DI±2061
2255 Author: Date:
2005 SEQUOIA (RM1146U)
AVC±LAN circuit
CIRCUIT DESCRIPTION
Each unit of the rear seat audio system connected to the AVC±LAN (communication bus) transfers the signal
of each switch by communication.
When a short to +B or short to ground occurs in this AVC± LAN, the audio system will not function normally
as communication is discontinued.
WIRING DIAGRAM
DIDAN±01