TOYOTA SEQUOIA 2001 Service Repair Manual

± DIAGNOSTICSMULTIPLEX COMMUNICATION SYSTEM
DI±1939
2133 Author: Date:
2005 SEQUOIA (RM1146U)
2 Check wire harness and connector between automatic light control sensor and
body ECU.
PREPARATION:
Disconnect connector ºA27º of the automatic light control sensor and connector ºB6º of the body ECU.
CHECK:
Measure the resistance according to the values in the table below.
OK:
Tester connection (Symbols)ConditionSpecified condition
A27±4 ± B6±12 (CLTS)AlwaysBelow 1 W
A27±1 ± B6±4 (CLTB)AlwaysBelow 1 W
A27±3 ± B6±3 (CLTE)AlwaysBelow 1 W
A27±4 ± Body groundAlways10 kW or higher
A27±1 ± Body groundAlways10 kW or higher
A27±3 ± Body groundAlways10 kW or higher
NG Repair or replace wire harness or connector.
OK
Replace the body ECU.

DI±1940
± DIAGNOSTICSMULTIPLEX COMMUNICATION SYSTEM
2134 Author: Date:
2005 SEQUOIA (RM1146U)
DTC B1262 A/C ECU communication stop
CIRCUIT DESCRIPTION
This DTC is indicated when communication fails between the integration control and panel and the body
ECU.
DTC No.DTC Detecting ConditionTrouble Area
B1262No communication from integration control and panel for more
than 10 seconds.
A/C ECU (Integration control and panel)

Wire harness

Body ECU
DIDFI±01

I28469
I19
Integration Control
and Panel
Body ECU
I18
Ignition SW Combination Meter
F10
FL Block
To Ignition
Switch J43
J/C
IG BatteryDOME ALTAM1CIG
ACC
AM1
Short Pin
J/CMPX±
ACC
+B MPX+ MPX2
IG+
GND C5
B5
J15
1E
1L
1JJ15
1E1C
1C
2D 2C3A 3E
3A 3E
O BR WW±L
O BRPP
P
R
R±L
R±L L±Y LG±B
DD 32
2413
3
11
31 1
1
8 6 20
1
52 8 5
4
13
6 6 16
151
2
10 Instrument Panel J/B
Engine Room J/BSub J/B No.3
AA
± DIAGNOSTICSMULTIPLEX COMMUNICATION SYSTEM
DI±1941
2135 Author: Date:
2005 SEQUOIA (RM1146U)
WIRING DIAGRAM

DI±1942
± DIAGNOSTICSMULTIPLEX COMMUNICATION SYSTEM
2136 Author: Date:
2005 SEQUOIA (RM1146U)
INSPECTION PROCEDURE
1 Check air conditioning system.
CHECK:
Check the operation of the air conditioning system.
OK:
The air conditioning system operates normally.
NG Go to air conditioning system
(See page DI±2301).
OK
2 Check wire harness (Integration control and panel ± combination meter, integra-
tion control and panel ± body ECU).
PREPARATION:
Disconnect connector ºB5º of the body ECU connector, ºI19º of the integration control and panel and connec-
tor ºC5º of the combination meter.
CHECK:
Measure the resistance according to the values in the table below.
OK:
Tester connection (Symbols)ConditionSpecified condition
C5±32 ± I19±13 (MPX±)AlwaysBelow 1 W
B5±24 (MPX2) ± I19±3 (MPX+)AlwaysBelow 1 W
C5±32 ± Body groundAlways10 kW or higher
B5±24 (MPX2) ± Body groundAlways10 kW or higher
NG Repair or replace wire harness.
OK
Replace integration control and panel.
If the problem recurs even after replacement, replace the body ECU.

± DIAGNOSTICSMULTIPLEX COMMUNICATION SYSTEM
DI±1943
2137 Author: Date:
2005 SEQUOIA (RM1146U)
DTC B1271 Combination meter ECU communica-
tion stop
CIRCUIT DESCRIPTION
This DTC is indicated when communication fails between the combination meter and body ECU.
DTC No.DTC Detecting ConditionTrouble Area
B1271No communication from combination meter for more than 10
seconds.
Combination meter

Wire harness

Body ECU
DIDFJ±01

I28470
Back Door ECUCombination Meter
I19
A/C ECU
(Integration Control and Panel)
Instrument Panel J/B
I18
Ignition SW
Engine Room J/B
Instrument Panel J/B
J8
J/C F10
Fusible
Link Block
Battery
IEC6 B11
BF1BD2
J34J33C5
C5
C6 1J
1C1D
1H
1J 1C
2C 2D
2C
1D 1F C6 Short Pin
ECU±B
AM2IGN1
IG2 AM2MPX1
MPX±LG±B LG±RLG±R
LG±R
LG±B
W±R
B±O W±R
B±R
W±R W±R
W±R
W±R
W±B
BR B
BABH 231
32
23
24 67
13
3
29
11
5 637
1 8
1
9
612
5 4J/C DI±1944
± DIAGNOSTICSMULTIPLEX COMMUNICATION SYSTEM
2138 Author: Date:
2005 SEQUOIA (RM1146U)
WIRING DIAGRAM

± DIAGNOSTICSMULTIPLEX COMMUNICATION SYSTEM
DI±1945
2139 Author: Date:
2005 SEQUOIA (RM1146U)
INSPECTION PROCEDURE
1 Check combination meter.
CHECK:
Start the engine and check that the speed meter and tachometer operate normally.
HINT:
With this inspection, the combination meter CPU can be diagnosed if it works normally or not.
OK:
Speed meter and tachometer operate normally.
NG Go to combination system (See page DI±1610).
OK
2 Check wire harness and connector (Combination meter ± back door ECU, com-
bination meter ± integration control and panel).
PREPARATION:
Disconnect connector ºB11º of the back door ECU, connector ºC5º of the combination meter and connector
ºI19º of the integration control and panel.
CHECK:
Measure the resistance according to the values in the table below.
OK:
Tester connection (Symbols)ConditionSpecified condition
B11±2 (MPX1) ± C5±31AlwaysBelow 1 W
I19±13 (MPX±) ± C5±32AlwaysBelow 1 W
B11±2 (MPX1) ± Body groundAlways10 kW or higher
I19±13 (MPX±) ± Body groundAlways10 kW or higher
NG Repair or replace wire harness.
OK
Replace the combination meter.
If the problem recurs even after replacement, replace the body ECU.

DI±1946
± DIAGNOSTICSMULTIPLEX COMMUNICATION SYSTEM
2140 Author: Date:
2005 SEQUOIA (RM1146U)
DTC B1272 Memory seat ECU communication stop (w/
Driving position memory)
CIRCUIT DESCRIPTION
This DTC is indicated when communication fails between the memory seat ECU & switch and body ECU.
DTC No.DTC Detecting ConditionTrouble Area
B1272No communication from memory seat ECU & switch for more
than 10 seconds.
Memory seat ECU & switch

Wire harness

Body ECU
DIDFK±01

I28471
Combination MeterMemory Seat ECU
& SW
Sub J/B No. 3J/C
J24
J/C
Instrument Panel J/B
F10
Fusible Link BlockI18
Ignition SW
Engine Room J/B
Battery
BHJ24
J/C J/C
J/C C5 J33 BI2 M6J34
J31 J32
3A 3AJ33 J34
J33 J34BI2
BI2 BI2
M6
M6 M7
AM1 ECU±IG
1F
1L
1J 1E 1G1C
1 4
6
1 16
2
1C
2 4
PWR SEAT
1 2
M7 BI2 ECU±B
Short Pin
2D 2C18 ALT
IG1 AM1 12
BB
W±B
W±B W±B
B58W W±L
W±R W±RB±Y B±R
L±O
3 W±R
W±RW±R W±R B±R B±R B±R L±O
L±O L±O L±O
3 111 8151641
5
A 9 C
A GG A
WWW17 30
CL
I FMPX1
+B
IG
SYSB
GND 1 4
± DIAGNOSTICSMULTIPLEX COMMUNICATION SYSTEM
DI±1947
2141 Author: Date:
2005 SEQUOIA (RM1146U)
WIRING DIAGRAM

DI±1948
± DIAGNOSTICSMULTIPLEX COMMUNICATION SYSTEM
2142 Author: Date:
2005 SEQUOIA (RM1146U)
INSPECTION PROCEDURE
1 Check power seat control system (w/ driving position memory).
CHECK:
Check the operation of the power seat.
OK:
The power seat control system operates normally.
NG Go to power source circuit (See page DI±1514).
OK
2 Check wire harness (Memory seat ECU & switch ± combination meter).
PREPARATION:
Disconnect connector ºM6º of the memory seat ECU and ºC5º of the combination meter.
CHECK:
Measure the resistance according to the values in the table below.
OK:
Tester connection (Symbols)ConditionSpecified condition
M6±1 (MPX1) ± C5±30AlwaysBelow 1 W
M6±1 (MPX1) ± Body groundAlways10 kW or higher
NG Repair or replace wire harness or connector.
OK
Replace memory seat ECU & switch.
If the problem recurs even after replacement, replace the body ECU.