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 (Busline) 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.
IN±26± INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
26 Author: Date:
2005 SEQUOIA (RM1146U)
2. SYMPTOM CONFIRMATION AND DIAGNOSTIC TROUBLE CODE CHECK
The diagnostic system in the SEQUOIA fulfills various functions. The first function is the Diagnostic Trouble
Code Check in which a malfunction in the signal circuits to the ECU is stored in code in the ECU memory
at the time of occurrence, to be output by the technician during troubleshooting. Another function is the Input
Signal Check which checks if the signals from various switches are sent to the ECU correctly.
By using these check functions, the problem areas can be narrowed down quickly and troubleshooting can
be performed effectively. Diagnostic functions are incorporated in the following systems in the SEQUOIA.
SystemDiagnostic Trouble
Code CheckInput Signal Check
(Sensor Check)Diagnostic Test
Mode (Active Test)
1. Engine (with Check
Mode)
2. Automatic Transmission (with Check
Mode)
3. Air Suspension Control System (with Check
Mode)
4. Tire Pressure Warning System
5. ABS with EBD & BA & TRAC & VSC System
6. Can Communication System
7. Supplemental Restraint System (with Check
Mode)
8. Power Seat Control System w/ Driving Position Memory
9. Cruise Control System
10.Engine Immobilizer System
11. Combination Meter System
12.Sliding Roof System
13.Body Control System
14.Driver Door Control System
15.Passenger Door Control System
16.Back Door Control System
17.Multiplex Communication System
18.Audio System
19.Rear Seat Audio System
20.Rear Seat Entertainment System
21.Air Conditioning System
In diagnostic trouble code check, it is very important to determine whether the problem indicated by the diag-
nostic trouble code is still occurring or occurred in the past but returned to normal at present. In addition,
it must be checked in the problem symptom check whether the malfunction indicated by the diagnostic
trouble code is directly related to the problem symptom or not. For this reason, the diagnostic trouble codes
should be checked before and after the symptom confirmation to determine the current conditions, as shown
in the table on the next page. If this is not done, it may, depending on the case, result in unnecessary trouble-
shooting for normally operating systems, thus making it more difficult to locate the problem, or in repairs not
pertinent to the problem. Therefore, always follow the procedure in correct order and perform the diagnostic
trouble code check.
I28735
Separate Type Amplifier:
Steering Pad Switch
AVC±LAN Speakers
Sound SignalOperation
Signal
Radio
Receiver
Assy Stereo
Component
Amplifier
Assy
Multi±display
Controller
Assy (*1)
Rear Seat Audio
Controller (*2)
*1: w/ Rear Seat Entertainment System
*2: w/Rear Seat Audio System
Display Signal DI±1958
± DIAGNOSTICSAUDIO SYSTEM
2152 Author: Date:
2005 SEQUOIA (RM1146U)
DI±1970
± DIAGNOSTICSAUDIO SYSTEM
2164 Author: Date:
2005 SEQUOIA (RM1146U) (*1) TX1+ (R19±9) ±
GND (R4±20)
L ± BRAVC±LAN
communication signalIgnition switch ON2 to 3 V
(*1) TX1± (R19±10) ±
GND (R4±20)LG ± BRAVC±LAN
communication signalIgnition switch ON2 to 3 V
(*1) SLD1 (R19±14) ±
Body groundShielded ±
Body groundShield groundAlwaysBelow 1 V
(*1) RSR+ (R19±15) ±
GND (R4±20)W ± BRSound signal
(Right output)Audio system is playing
A waveform synchro-
nized with sound is out-
put
(*1) RSR± (R19±16) ±
GND (R4±20)G ± BRSound signal
(Right output)Audio system is playing
A waveform synchro-
nized with sound is out-
put
(*1) RSL+ (R19±17) ±
GND (R4±20)B ± BRSound signal
(Left output)Audio system is playing
A waveform synchro-
nized with sound is out-
put
(*1) RSL± (R19±18) ±
GND (R4±20)R ± BRSound signal
(Left output)Audio system is playing
A waveform synchro-
nized with sound is out-
put
(*1) RMU (R19±19) ±
GND (R4±20)R±W ± BRMUTE signalAudio system is playing "
changing modeAbove 3.5 V "
Below 1 V
(*1) S±GND (R20±1) ±
Body groundShielded ±
Body groundShield groundAlwaysBelow 1 V
(*1) R+ (R20±2) ±
GND (R4±20)W ± BRSound signal
(Right input)Rear seat entertainment system is
playingA waveform synchro-
nized with sound is out-
put
(*1) R± (R20±3) ±
GND (R4±20)G ± BRSound signal
(Right input)Rear seat entertainment system is
playingA waveform synchro-
nized with sound is out-
put
(*1) L+ (R20±4) ± GND (R4±20)B ± BRSound signal
(Left input)Rear seat entertainment system is
playingA waveform synchro-
nized with sound is out-
put
(*1) L± (R20±5) ± GND (R4±20)R ± BRSound signal
(Left input)Rear seat entertainment system is
playingA waveform synchro-
nized with sound is out-
put
(*1) MUTE (R20±6) ±
GND (R4±20)R±G ± BRMUTE signalRear seat entertainment system is
playing " changing modeAbove 3.5 V "
Below 1 V
(*2) TX1+ (R19±9) ±
GND (R4±20)L ± BRAVC±LAN
communication signalIgnition switch ON2 to 3 V
(*2) TX1± (R19±10) ±
GND (R4±20)LG ± BRAVC±LAN
communication signalIgnition switch ON2 to 3 V
(*2) SLD1 (R19±14) ±
Body groundShielded ±
Body groundShield groundAlwaysBelow 1 V
(*2) RSR+ (R19±15) ±
GND (R4±20)W ± BRSound signal
(Right output)Audio system is playing
A waveform synchro-
nized with sound is out-
put
(*2) RSR± (R19±16) ±
GND (R4±20)G ± BRSound signal
(Right output)Audio system is playing
A waveform synchro-
nized with sound is out-
put
(*2) RSL+ (R19±17) ±
GND (R4±20)B ± BRSound signal
(Left output)Audio system is playing
A waveform synchro-
nized with sound is out-
put
(*2) RSL± (R19±18) ±
GND (R4±20)R ± BRSound signal
(Left output)Audio system is playing
A waveform synchro-
nized with sound is out-
put
(*2) RMU (R19±19) ±
GND (R4±20)R±W ± BRMUTE signalAudio system is playing "
changing modeAbove 3.5 V "
Below 1 V
I28313
R2R3R19
± DIAGNOSTICSAUDIO SYSTEM
DI±1971
2165 Author: Date:
2005 SEQUOIA (RM1146U)
*1: w/ Rear seat entertainment system
*2: w/ Rear seat audio system
2. RADIO RECEIVER ASSY (BUILT±IN TYPE AMPLIFIER)
Symbols (Terminal No.)Wiring ColorTerminal DescriptionConditionSpecification
FR+ (R2±1) ± GND (R2±7)LG ± BRSound signal (Front Right)Audio system is playing
A waveform synchro-
nized with sounds is
output
FL+ (R2±2) ± GND (R2±7)P ± BRSound signal (Front Left)Audio system is playing
A waveform synchro-
nized with sounds is
output
ACC+B (R2±3) ± GND (R2±7)GR ± BRAccessory (ON)Turn ignition switch to OFF " ACCBelow 1 V "
10 to 14 V
BU+B (R2±4) ± GND (R2±7)L±Y ± BRBatteryAlways10 to 14 V
FR± (R2±5) ± GND (R2±7)L ± BRSound signal (Front Right)Audio system is playing
A waveform synchro-
nized with sounds is
output
FL± (R2±6) ± GND (R2±7)V ± BRSound signal (Front Left)Audio system is playing
A waveform synchro-
nized with sounds is
output
GND (R2±7) ± Body groundBR ±
Body groundGroundAlwaysBelow 1 V
ANT+B (R2±8) ± GND (R2±7)B±R ± BRPower source of antennaRadio switch ON and AM or FM10 to 14 V
ILL+ (R2±10) ± GND (R2±7)G ± BRIllumination (rheostat) sig-
nalLight control switch OFF " TAIL or
HEADBelow 1 V "
10 to 14 V
RR+ (R3±1) ± GND (R2±7)R ± BRSound signal (Rear Right)Audio system is playing
A waveform synchro-
nized with sounds is
output
RL+ (R3±2) ± GND (R2±7)B ± BRSound signal (Rear Left)Audio system is playing
A waveform synchro-
nized with sounds is
output
RR± (R3±3) ± GND (R2±7)W ± BRSound signal (Rear Right)Audio system is playing
A waveform synchro-
nized with sounds is
output
ILL± (R3±5) ± GND (R2±7)W±G ± BRIllumination (rheostat) sig-
nalLight control switch OFF " TAIL or
HEADBelow 1 V "
10 to 14 V
RL± (R3±6) ± GND (R2±7)Y ± BRSound signal (Rear Left)Audio system is playing
A waveform synchro-
nized with sounds is
output
GND (R19±6) ± GND (R2±7)BR±W ± BRSteering pad switch
groundAlwaysBelow 1 V
DI±1982
± DIAGNOSTICSAUDIO SYSTEM
2176 Author: Date:
2005 SEQUOIA (RM1146U)DE
*4
Slave Reset (Momentary Inter-
ruption)After the engine was started, component shown
by sub code was disconnected from system.
1. Power source circuit (Stereo
component amplifier assy).
2. Power source circuit (Rear seat
audio controller). *6
3. Power source circuit (Multi±dis-
play controller sub±assy) *7
4. AVC±LAN circuit (Radio receiver
assy ± Stereo component ampli-
fier assy).
5. AVC±LAN (Radio receiver assy
± Rear seat audio controller). *6
6. AVC±LAN (Radio receiver assy
± Multi±display controller sub±
assy). *7
7. Replace stereo component am-
plifier assy.
8. Replace rear seat audio control-
ler. *6
9. Replace multi±display controller
sub±assy. *7DI±1993
DI±2058
DI±2110
DI±2023
DI±2061
DI±2139
±
±
±
DF
*4Master Error
Due to defective cognition of component with a
display, master function is switched to audio
equipment.
1. Power source circuit (Stereo
component amplifier assy).
2. Power source circuit (Rear seat
audio controller). *6
3. Power source circuit (Multi±dis-
play controller sub±assy) *7
4. AVC±LAN circuit (Radio receiver
assy ± Stereo component ampli-
fier assy).
5. AVC±LAN (Radio receiver assy
± Rear seat audio controller). *6
6. AVC±LAN (Radio receiver assy
± Multi±display controller sub±
assy). *7
7. Replace stereo component am-
plifier assy.
8. Replace rear seat audio control-
ler. *6
9. Replace multi±display controller
sub±assy. *7DI±1993
DI±2058
DI±2110
DI±2023
DI±2061
DI±2139
±
±
±
HINT:
*1: This code may be recorded depending on the battery condition or engine start voltage even if no
failure is detected.
*2: If the power connector is disconnected after the engine starts, this code is recorded after 180 se-
conds.
*3: This code may be stored if the ignition key is turned to the START position again with the engine
running.
*4: This code may be stored if the ignition key is held in the START position for 1 minute or more before
returning to the ON position.
*5: If the device is reported as not existing during verification, check the power source circuit and AVC±
LAN circuit for the device.
*6: w/ Rear seat audio system only.
*7: w/ Rear seat entertainment system only.
± DIAGNOSTICSAUDIO SYSTEM
DI±1985
2179 Author: Date:
2005 SEQUOIA (RM1146U)
Logical address: 01 (Communication control) continued
DTCNameDiagnosisVerificationSee page
DF
*4Master Error
Due to defective condition of component with a
display, master function is switched to audio
equipment.
Error occurs in communication between sub±
master (audio) and master component.
1. Power source circuit (Radio re-
ceiver assy).
2. Power source circuit (Stereo
component amplifier assy).
3. AVC±LAN circuit (Radio receiver
assy ± Stereo component ampli-
fier assy).
4. AVC±LAN (Radio receiver assy
± Rear seat audio controller). *5
5. AVC±LAN (Radio receiver assy
± Multi±display controller sub±
assy). *6
6. Replace radio receiver assy.
7. Replace stereo component am-
plifier assy.DI±1990
DI±1993
DI±2023
DI±2061
DI±2139
±
±
E0
*1Registration Completion
Instruction ErrorºRegistration Completion Instructionº command
from master cannot be received.Since this DTC is provided for engi-
neering purposes, it may be de-
tected when no actual failure exists.
±
E1
*1Audio processor ON errorWhile source equipment is operating, AMP output
stops.
1. Power source circuit (Radio re-
ceiver assy).
2. Power source circuit (Stereo
component amplifier assy).
3. AVC±LAN circuit (Radio receiver
assy ± Stereo component ampli-
fier assy).
4. AVC±LAN (Radio receiver assy
± Rear seat audio controller). *5
5. AVC±LAN (Radio receiver assy
± Multi±display controller sub±
assy). *6
6. Replace radio receiver assy.
7. Replace stereo component am-
plifier assy.DI±1990
DI±1993
DI±2023
DI±2061
DI±2139
±
±
E2ON/OFF Instruction Parameter
ErrorError occurs in ON/OFF controlling command
from radio receiver assy.Replace radio receiver assy.±
E3
*1Registration Request Transmis-
sionRegistration Request command is output from
slave component.Since this DTC is provided for engi-
neering purposes, it may be de-
tected when no actual failure exists.
±
HINT:
*1: This code may be recorded depending on the battery condition or engine start voltage even if no
failure is detected.
*2: This code may be stored if the ignition key is turned to the START position again with the engine
running.
*3: This code may be stored if the ignition key is held in the START position for one minute or more
before returning to the ON position.
*4: If the device is reported as not existing during verification, check the power source circuit and AVC±
LAN circuit for the device.
*5: w/ Rear seat audio system only.
*6: w/ Rear seat entertainment system only.
DIDAV±01
± DIAGNOSTICSREAR SEAT ENTERTAINMANT SYSTEM
DI±2081
2275 Author: Date:
2005 SEQUOIA (RM1146U)
SYSTEM DESCRIPTION
1. Outline
As a unique feature of Rear Seat Entertainment (RSE) system, the front and rear seat occupants can
enjoy different audio±visual modes at the same time. Thus, this system offers enhanced entertainment
to the rear seat occupants.
The rear seat occupants can control the audio±visual modes with the remote controller (switch assy),
and listen to audio by using wired or wireless headphones.
The RSE system is controlled by the multi±display controller, and the communication among the audio
head unit, rear display assembly, and DVD player is established via an AVC±LAN (Audio Visual Com-
munication±Local Area Network).
2. Function of Main Component
Television Display Assy
Displays DVD and video images in accordance with video signals from the RSE ECU.
Receives signals from the remote controller and outputs them to the RSE ECU.
Outputs audio signals to the wireless headphones in the form of infrared signals.
Displays the audio±visual control screen.
Displays the adjustment screen.
Displays the diagnosis screen.
The diagnosis screen appears when the diagnosis mode is started on the audio head unit.
Audio Head Unit
w/ Navigation system:
Radio and navigation assy
w/o Navigation system:
Radio receiver assy
Outputs audio signals to the RSE ECU and the stereo component amplifier.
Outputs a request to the RSE ECU to start the diagnosis mode.
RSE ECU (Multi±display Controller)
Processes video and audio signals from the DVD player and video player and audio signals from the
audio head unit, and outputs them to the television display assembly and headphone terminals.
Controls the distribution of the audio±visual mode to the front (audio head unit) and the rear (RSE).
Remote Controller (Switch Assy)Outputs various control signals of the RSE system to the television display assembly in the form of in-
frared signals.
Wireless Headphone
Receives the audio signals from the television display assembly in the form of infrared signals.
Volume adjustment of the wireless headphone can be done by using the volume equipped on the wire-
less headphone.
Headphone TerminalOutputs audio signals to the wired headphones that are connected.
Adjusts the volume of the wired headphones in accordance with volume control.
VTR TerminalThis terminal is for connecting the video player's video and audio output terminals.