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.
PP3JT±01
± PREPARATIONBODY
PP±75
133 Author: Date:
2005 SEQUOIA (RM1146U)
BODY
SST (Special Service Tools)
09082±00700SRS Airbag Deployment ToolSEAT BELT PRETENSIONER
09082±00740Airbag Deployment Wire
Sub±harness No.2SEAT BELT PRETENSIONER
09806±30010Windshield Moulding RemoverWINDSHIELD
ROOF DRIP SIDE FINISH
MOULDING
09812±00010Door Hinge Set Bolt WrenchFRONT DOOR
± SERVICE SPECIFICATIONSBODY
SS±49
191 Author: Date:
2005 SEQUOIA (RM1146U) Power window regulator x Door panel
5.55649 in.´lbf
Back door lock x Door panel8.08271 in.´lbf
FRONT WIPER AND WASHER±±±
Wiper link x Body5.55649 in.´lbf
Wiper motor x Wiper link5.55649 in.´lbf
Wiper arm x Wiper link2020415
REAR WIPER AND WASHER±±±
Rear wiper motor x Body5.55649 in.´lbf
Wiper arm x Rear wiper motor5.55649 in.´lbf
BODY OUTSIDE MOULDING±±±
Rear bumper cover x Rear bumper extension5.05043 in.´lbf
WINDSHIELD±±±
Inner rear view mirror set torx screw2.52522 in.´lbf
SLIDING ROOF±±±
Sliding roof housing x Body5.55649 in.´lbf
INSTRUMENT PANEL±±±
Front passenger airbag assembly x Instrument panel5.05144 in.´lbf
Front passenger airbag assembly x Instrument panel reinforcement2020415
Steering wheel x Steering wheel pad8.89078 in.´lbf
Box panel sub±assembly x Floor panel4040830
FRONT SEAT (Power Adjuster Type)±±±
w/ Side airbag:
Seatback cover bracket x Seat frame assembly5.55649 in.´lbf
Armrest x Seat frame assembly3738027
Front seat x Body3738027
FRONT SEAT (Manual Adjuster Type)±±±
w/ Side airbag:
Seatback cover bracket x Seat frame assembly5.55649 in.´lbf
Armrest x Seat frame assembly3738027
Front seat x Body3738027
REAR NO.1 SEAT (Separate Type)±±±
Rear seat cushion hinge x Body3738027
LH rear seat lock x Seat cushion frame4344032
Rear seat reclining adjuster x Seat cushion frame4344032
Rear seat reclining adjuster x Seatback frame4344032
RH rear seat lock x Seat cushion frame6465347
REAR NO. 1 SEAT (Split Type LH)±±±
Rear seat cushion hinge x Body4344032
Rear No. 1 seat outer adjuster x Seat cushion frame4344032
Rear No. 1 seat outer adjuster x Seatback frame4344032
Rear No. 1 seat inner adjuster x Seat cushion frame4344032
Rear No. 1 seat inner adjuster x Seatback frame4243031
Rear seat shoulder belt guide x Seatback frame3738027
REAR NO.1 SEAT (Split Type RH)±±±
Rear seat cushion hinge x Body3738027
Rear seat lock x Seat cushion frame4344032
SS±50
± SERVICE SPECIFICATIONSBODY
192 Author: Date:
2005 SEQUOIA (RM1146U) Rear seat reclining adjuster x Seat cushion frame
4344032
Rear seat reclining adjuster x Seatback frame4344032
REAR NO. 2 SEAT±±±
Seat adjuster x Seat cushion frame1919514
No .2 seat reclining adjuster x Seat cushion frame4344032
No. 2 seat reclining adjuster x Seatback frame4344032
SEAT BELT±±±
Front seat outer belt shoulder anchor x Adjustable anchor4243032
Front seat outer belt floor anchor x Body4243032
Front seat outer belt retractor x Body4243032
Adjustable anchor x Body4243032
Front seat inner belt x Front seat4243032
Rear No. 1 seat outer belt shoulder anchor x Adjustable anchor4243032
Rear No. 1 seat outer belt floor anchor x Body4243032
Rear No. 1 seat outer belt retractor x Body Upper bolt:8.58776 in.´lbf
Rear No. 1 seat outer belt retractor x Body Lower bolt:4243032
Rear outer belt retractor x Rear No. 1 seat4243032
Rear outer belt floor anchor x Rear seat lock4243032
Rear No. 2 seat outer belt shoulder anchor x Body4243032
Rear No. 2 seat outer belt floor anchor x Body4243032
Rear No. 2 seat outer belt retractor x Body Upper bolt:8.58776 in.´lbf
Rear No. 2 seat outer belt retractor x Body Lower bolt:4243032
Rear No.2 seat outer center belt x Body4243032
Rear No. 2 inner belt x Rear No. 2 seat4243032
SIDE STEP±±±
Side step bracket x Body1919514
Step plate x Side step bracket4.95043 in.´lbf
ROOF RACK±±±
Front leg x Body1111 58
Center support x Body1111 58
Rear leg x Body1111 58
SPOILER±±±
Rear spoiler x Body121208
DI±1606
± DIAGNOSTICSCOMBINATION METER SYSTEM
1800 Author: Date:
2005 SEQUOIA (RM1146U)
Input and output signals of each ECU
Transmitting ECU
(transmitter)Receiving ECUSignalsCommunication
method
A/C ECU
Combination meter
Driver door control ECU
Passenger door control ECU
Temperature dataBEAN
A/C ECUCombination meterEngine coolant temperature dataBEAN
Combination meter
A/C ECU
Body ECU
Driver door control ECU
Passenger door control ECU
Back door ECU
Vehicle speed signalBEAN
Combination meterBody ECU
Seat control ECUShift position signalBEAN
Combination meter
A/C ECU
Body ECU
Driver door control ECU
Passenger door control ECU
Back door ECU
Meter activation signalBEAN
Combination meterA/C ECUDisplay unit demand signalBEAN
Combination meterBody ECUEngine system signalBEAN
Body ECU
A/C ECU
Combination meter
Driver door control ECU
Passenger door control ECU
Seat control ECU
Sliding roof control ECU
Back door ECU
Diagnosis tool demand signalBEAN
Body ECUA/C ECU
Combination meterBody control system signal (HEAD
signal, TAIL signal)BEAN
Body ECU
Combination meter
Driver door control ECU
Passenger door control ECU
Seat control ECU
Sliding roof control ECU
Back door ECU
Body control system signal (IG
signal, ACC signal, All door cour-
tesy lamp signal, Door lock signal,
Door unlock signal)
BEAN
Body ECU
Combination meter
Driver door control ECU
Passenger door control ECU
Seat control ECU
Sliding roof control ECU
Back door ECU
Body ECU activation signalBEAN
Body ECU
Combination meter
Driver door control ECU
Seat control ECUBody control system signal (KSW
signal)BEAN
Body ECU
Combination meter
Driver door control ECU
Passenger door control ECU
Seat control ECUDoor condition signal (Driver side
door courtesy lamp signal, Pas-
senger side door courtesy signal)
BEAN
± DIAGNOSTICSCOMBINATION METER SYSTEM
DI±1607
1801 Author: Date:
2005 SEQUOIA (RM1146U)Driver door control ECU
Combination meter
Body control ECU
Passenger door control ECU
Seat control ECU
Sliding roof control ECU
Back door ECU
Driver door control ECU activation
signalBEAN
Passenger door control ECU
Combination meter
Body control ECU
Driver door control ECU
Seat control ECU
Sliding roof control ECU
Back door ECU
Passenger door control ECU ac-
tivation signalBEAN
Sliding roof control ECU
Combination meter
Body control ECU
Driver door control ECU
Passenger door control ECU
Back door ECU
Sliding roof control ECU activation
signalBEAN
Seat control ECU
Combination meter
Body control ECU
Driver door control ECU
Passenger door control ECU
Seat control ECU activation signalBEAN
Back door ECU
Combination meter
Body control ECU
Driver door control ECU
Passenger door control ECU
Seat control ECU
Back door control ECU activation
signalBEAN
A/C ECU
Combination meter
Driver door control ECU
Passenger door control ECU
Seat control ECU
Sliding roof control ECU
Back door ECU
Back door ECUDiagnosis tool answer signalBEAN
DID64±01
± DIAGNOSTICSSLIDING ROOF SYSTEM
DI±1661
1855 Author: Date:
2005 SEQUOIA (RM1146U)
SLIDING ROOF 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