TOYOTA SEQUOIA 2001 Service Repair Manual

DIDFN±01
B78765I28978
Battery
Serial Communication Switch
ECUOn On
Off
ECULight
Motor
Heater
Solenoid
Conceptual Drawing 
I28977
Frame
Data
Header End Message
± DIAGNOSTICSMULTIPLEX COMMUNICATION SYSTEM
DI±1889
2083 Author: Date:
2005 SEQUOIA (RM1146U)
SYSTEM DESCRIPTION
Basic of MPX (Multiplex Communication)
1. General
The SEQUOIA multiplex communication system uses serial communication, which converts multiple pieces
of information into serial communication data. As a result, they can be transmitted through a single commu-
nication wire.
Serial communication data consists of bits and frames. A bit is the basic unit that represents the amount of
information. A bit is represented by a binary value º0º or º1º. A frame is a body of data that is transmitted
together. A frame contains a ºheaderº that indicates the beginning of the data and an ºend messageº that
indicates the end of the data.

B78774I28976
ECU
ECUECU
ECU Daisy
Chain
Open DI±1890
± DIAGNOSTICSMULTIPLEX COMMUNICATION SYSTEM
2084 Author: Date:
2005 SEQUOIA (RM1146U)
2. Network Style
Based on serial communication, various ECUs are connected on a network to exchange various pieces of
information. Such a system is called a multiplex communication system.
The BEAN (Body Electronics Area Network) uses the ring and bus styles of networks to connect ECUs.
This connection style is called a daisy chain. In the daisy chain, communication can be maintained
even if there is an area that has an open circuit.

I03343I03344I03345I03977
ECU
ECU
ECU
ECU
ECU
ECU Open Open
ECU
ECU
Open
ECU Disconnection (DTC is detected)
Open (DTC is detected)
Open (DTC is not detected)
I03346
Body ECU
OpenOpen
Detects the DTCs for the
communication stop of the
3 ECUs. Example
± DIAGNOSTICSMULTIPLEX COMMUNICATION SYSTEM
DI±1891
2085 Author: Date:
2005 SEQUOIA (RM1146U)
3. DIAGNOSIS SYSTEM
(a) If a DTC for an ECU communication stop is indicated, a
connector may be disconnected or there may be open cir-
cuits on 2 or more communication buses. When there is
an open circuit on only 1 communication bus, no DTC will
be detected.
(b) If 2 communication buses are open at the position shown
in the illustration, DTCs for the ECU communication stop
between these 2 buses are indicated.

DI3IO±11
Customer Problem Analysis
Vehicle Brought to Workshop
Problem Symptom ConfirmationSymptom Simulation Problem does not
occur
Check DTC
Normal code
Problem Symptoms Table
Identification of Problem
Repair
Confirmation Test
EndTitles inside
are titles of pages in this
manual, with the page number indicated in
the bottom portion. See the indicated pages
for detailed explanations.
1
23
4
6
8P. IN±24
*1P. DI±1893
P. DI±1904Malfunction code
Problem
occurs
Circuit Inspection
P. DI±1908 ± DI±1952
See page
Body control system
Driver door control system
Passenger door control systemSystem
DI±1682
DI±1780
DI±1816
DI±1610
Step 4, 8: Diagnostic steps permitting the use of the hand±held tester.*15
7
Combination meter system
Slide roof control system
DI±1662 DI±1852 Back door control system
Power seat control system
w/ Driving position memoryDI±1505
Supplemental restraint system
Air conditioning systemDI±1126
DI±2301 DI±1892
± DIAGNOSTICSMULTIPLEX COMMUNICATION SYSTEM
2086 Author: Date:
2005 SEQUOIA (RM1146U)
HOW TO PROCEED WITH TROUBLESHOOTING
Perform troubleshooting in accordance with the procedure on the following page.

DI3IP±10
MULTIPLEX COMMUNICATION SYSTEM Check Sheet
Inspector 's name:
Customer 's Name
Date VehicleVIN
Production Date
Licence Plate No.
Odometer Reading / /km
mile
Weather Conditions
When Problem
Occurred
Date Problem First Occurred
Frequency Problem Occurs
Weather
/ /
Once only Brought in
Malfunction
System
Outdoor Temperature
Fine Cloudy Rainy Snowy
Various/Others
Hot Warm Cool
Cold (Approx. °F ( °C))
Constant Sometimes ( times per day, month)
Driver Door Control System
Passenger Door Control System
Combination Meter System
Body Control System
Back Door Control System
Slide Roof Control System
Power Seat Control System (w/ Driving Position Memory)
Supplemental Restraint System
Air Condition System
± DIAGNOSTICSMULTIPLEX COMMUNICATION SYSTEM
DI±1893
2087 Author: Date:
2005 SEQUOIA (RM1146U)
CUSTOMER PROBLEM ANALYSIS CHECK

DIDFA±01
I27698
B5
B6B7
DI±1894
± DIAGNOSTICSMULTIPLEX COMMUNICATION SYSTEM
2088 Author: Date:
2005 SEQUOIA (RM1146U)
TERMINALS OF ECU
1. CHECK BODY ECU
(a) Disconnect the B5, B6 and B7 ECU connectors.
(b) Measure the resistance or voltage of each terminal of the wire harness side connector.
Standard:
Symbols (Terminal No.)Wiring ColorTerminal DescriptionConditionSpecified Condition
BDR (B6±2) ±
Body groundL±W ± Body ground+B (BATT) power supplyAlways10 to 14 V
IG (B7±6) ± Body groundB±R ± Body groundIgnition power supplyIgnition switch ON10 to 14 V
ACC (B7±10) ±
Body groundGR ± Body groundACC power supplyIgnition switch ACC10 to 14 V
OBD2 (B5±2) ±
Body groundG±R ± Body groundBus º+º lineDuring transmissionPulse generation
S+B (B6±1) ± Body groundW±L ± Body ground+B (BATT) power supplyAlways10 to 14 V
BECU (B6±5) ±
Body groundW±R ± Body ground+B (BATT) power supplyAlways10 to 14 V
WIG (B7±5) ± Body groundL±Y ± Body groundIgnition power supplyIgnition switch ON10 to 14 V
MPX3 (B7±20) ±
Body groundG±O ± Body groundMPX lineAlways10 kW or higher
MPX2 (B5±24) ±
Body groundL±Y ± Body groundMPX lineAlways10 kW or higher
MPX1 (B7±22) ±
Body groundW±L ± Body groundMPX lineAlways10 kW or higher
GND1 (B6±6) ±
Body groundW±B ± Body groundGroundAlwaysBelow 1 W
PRG ± GND1
(B5±5 ± B6±6)V ± W±BWireless transmitter signal
groundWireless door look receiver
communication circuit±
RDA ± GND1
(B5±4 ± B6±6)R±G ± W±BWireless transmitter signal
inputWireless door lock control
system is operatedBelow 1 V
RDA ± GND1
(B5±4 ± B6±6)R±G ± W±BWireless transmitter signal
inputWireless door lock control
system is not operated10 to 14 V
GSW
(B6±16)GR±RAir bag sensor commu-
nication signalAir bag sensor commu-
nication circuit±
CLTS (*1) ± GND1
(B6±12 ± B6±6)Y ± W±BAutomatic light control sen-
sor (Signal)Ignition switch OFFBelow 1 V
CLTS (*1) ± GND1
(B6±12 ± B6±6)Y ± W±BAutomatic light control sen-
sor (Signal)Ignition switch ONSignal waveform
CLTE (*1) ± GND1
(B6±3 ± B6±6)BR ± W±BAutomatic light control sen-
sor (Ground)AlwaysBelow 1 V

I18633
D22
± DIAGNOSTICSMULTIPLEX COMMUNICATION SYSTEM
DI±1895
2089 Author: Date:
2005 SEQUOIA (RM1146U) CLTB (*1) ± GND1
(B6±4 ± B6±6)
R±G ± W±BAutomatic light control sen-
sor (IG)Ignition switch OFFBelow 1 V
CLTB (*1) ± GND1
(B6±4 ± B6±6)R±G ± W±BAutomatic light control sen-
sor (IG)Ignition switch ON10 to 14 V
(*1): w/ Automatic Light Control
If the result is not as specified, there may be a malfunction on the wire harness side.
2. CHECK DRIVER DOOR ECU
(a) Disconnect the D22 ECU connector.
(b) Measure the resistance or voltage of each terminal of the wire harness side connector.
Standard:
Symbols (Terminals No.)Wiring ColorTerminal DescriptionConditionSpecified Condition
SIG (D22±21) ± Body groundB±R ±
Body groundIgnition power supplyIgnition switch ON10 to 14 V
CPUB (D22±23) ± Body groundW±R ±
Body ground+B (BATT) power supplyAlways10 to 14 V
MPX1 (D22±20) ± Body groundG±B ±
Body groundMPX lineAlways10 kW or higher
MPX2 (D22±8) ± Body groundW±L ±
Body groundMPX lineAlways10 kW or higher
BDR (D22±25) ± Body groundL±W ±
Body ground+B (BATT) power supplyAlways10 to 14 V
GND (D22±13) ± Body groundW±B ±
Body groundGroundAlwaysBelow 1 W
If the result is not as specified, there may be a malfunction on the wire harness side.

I18633
F18
w/ Driving Position Memory: DI±1896
± DIAGNOSTICSMULTIPLEX COMMUNICATION SYSTEM
2090 Author: Date:
2005 SEQUOIA (RM1146U)
3. CHECK FRONT PASSENGER DOOR ECU
(a) Disconnect the F18 ECU connector.
(b) Measure the resistance or voltage of each terminal of the wire harness side connector.
Standard:
Symbols (Terminals No.)Wiring ColorTerminal DescriptionConditionSpecified Condition
SIG (F18±21) ± Body groundB±R ±
Body groundIgnition power supplyIgnition switch ON10 to 14 V
BDR (F18±25) ± Body groundL±Y ±
Body ground+B (BATT) power supplyAlways10 to 14 V
MPX1 (F18±20) ± Body groundB ± Body groundMPX lineAlways10 kW or higher
MPX2 (F18±8) ± Body groundG±B ±
Body groundMPX lineAlways10 kW or higher
CPUB (F18±23) ± Body groundW±R ±
Body ground+B (BATT) power supplyAlways10 to 14 V
GND (F18±13) ± Body groundW±B ±
Body groundGroundAlwaysBelow 1 W
If the result is not as specified, there may be a malfunction on the wire harness side.

I18630
F18
w/o Driving Position Memory:
± DIAGNOSTICSMULTIPLEX COMMUNICATION SYSTEM
DI±1897
2091 Author: Date:
2005 SEQUOIA (RM1146U)
(a) Disconnect the F18 ECU connector.
(b) Measure the resistance or voltage of each terminal of the wire harness side connector.
Standard:
Symbols (Terminals No.)Wiring ColorTerminal DescriptionConditionSpecified Condition
SIG (F18±19) ± Body groundB±R ±
Body groundIgnition power supplyIgnition switch ON10 to 14 V
BDR (F18±20) ± Body groundL±Y ±
Body ground+B (BATT) power supplyAlways10 to 14 V
MPX1 (F18±10) ± Body groundB ± Body groundMPX lineAlways10 kW or higher
MPX2 (F18±11) ± Body groundG±B ±
Body groundMPX lineAlways10 kW or higher
CPUB (F18±12) ± Body groundW±R ±
Body ground+B (BATT) power supplyAlways10 to 14 V
GND (F18±8) ± Body groundW±B ±
Body groundGroundAlwaysBelow 1 W
If the result is not as specified, there may be a malfunction on the wire harness side.

I18632
S19
DI±1898
± DIAGNOSTICSMULTIPLEX COMMUNICATION SYSTEM
2092 Author: Date:
2005 SEQUOIA (RM1146U)
4. CHECK SLIDING ROOF ECU
(a) Disconnect the S19 ECU connector.
(b) Measure the resistance or voltage of each terminal of the wire harness side connector.
Standard:
Symbols (Terminals No.)Wiring ColorTerminal DescriptionConditionSpecified Condition
IG (S19±8) ± Body groundB±R ±
Body groundIgnition power supplyIgnition switch ON10 to 14 V
B (S19±5) ± Body groundL±W ±
Body ground+B (BATT) power supplyAlways10 to 14 V
MPX1 (S19±2) ± Body groundG±O ±
Body groundMPX lineAlways10 kW or higher
E (S19±7) ± Body groundW±B ±
Body groundGroundAlwaysBelow 1 W
If the result is not as specified, there may be a malfunction on the wire harness side.