Page 977 of 2572
- DIAGNOSTICSMULTIPLEX COMMUNICATION SYSTEM
05-2065
2255 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
DTC B1261 ECM (ENGINE ECU) COMMUNICATION
STOP
CIRCUIT DESCRIPTION
B1261 will be output when the communication between the ECM and multiplex network body ECU stops
for more than 10 seconds.
DTC No.DTC Detecting ConditionTrouble Area
B1261No communication from ECM for more than 10 secondsECM
Wire harness
0523Z-04
Page 978 of 2572
B78728
Engine Room J/BB10
Multiplex Network Body ECU
ECM
Combination Meter Assy (Meter ECU)J7
J/C E6
MREL
13E5
MPX2 4
IK3
MPX+9 BatteryBR
J2
J/C FL MAINMPX1
4
7 5 2I 2B
2F2B 2B
F7
FL Block
Assy6
15
EFI
No.1EFI
Relay
B-W W
IK2
E5 BATT
EH3
+B IK2
W-BW3
Y
A BBR
GR*
1
IE1
ED 10
11
E5
W W
W13E6
829
A E9 E7
11
BR 6
IL2 1 GR
GR
SB
C12
*
1: 2AZ-FE
*2: 3MZ-FEA
Sliding Roof
Contorl ECUMPX1 S20W
MPX1
*
2
*1
*2EE
+B2 E51
2 1
2
W
10 P-L18
E1 05-2066
- DIAGNOSTICSMULTIPLEX COMMUNICATION SYSTEM
2256 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
WIRING DIAGRAM
Page 979 of 2572
H45688
ECM
Multiplex Network Body ECUE5
B10
C12 Combination Meter Assy (Meter ECU)E6
- DIAGNOSTICSMULTIPLEX COMMUNICATION SYSTEM
05-2067
2257 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
INSPECTION PROCEDURE
1 CHECK CONTINUITY OF COMMUNICATION LINE
(a) Check the wire harness between the combination meter assy (meter ECU), ECM and multiplex net-
work body ECU
Page 980 of 2572

A53766
E7
E8E9 E6E5
05-2068
- DIAGNOSTICSMULTIPLEX COMMUNICATION SYSTEM
2258 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
(1) Disconnect the connectors of the meter assy, ECM and body ECU.
(2) Inspect the continuity between terminals E6-18 (MPX1) of the ECM vehicle's side connector and
B10-6 (MPX1) of the body ECU vehicle's side connector.
Standard:
Symbols (Terminal No.)Specified Condition
MPX1 (E6-18) @ MPX1 (B10-6)
(equipped with 1MZ-FE)Continuity
MPX1 (E6-18) @ MPX1 (B10-6)
(equipped with 2AZ-FE)Continuity
(3) Inspect the continuity between terminals E6-29 (MPX2) of the ECM vehicle's side connector and
C12-9 (MPX+) of the meter assy vehicle's side connector.
Standard:
Symbols (Terminal No.)Specified Condition
MPX2 (E6-29) @ MPX+ (C12-9)
(equipped with 1MZ-FE)Continuity
MPX2 (E6-29) @ MPX+ (C12-9)
(equipped with 2AZ-FE)Continuity
NG REPAIR OR REPLACE HARNESS AND
CONNECTOR
OK
2 CHECK ECM
(a) Inspect the ECM (power source input).
NOTICE:
Do not disconnect the ECM connector. The inspection should be started from the backside of the
connector.
Standard:
Symbols (Terminal No.)In/OutputConditionSpecified Condition
BATT (E5-3) @ Body groundInputConstant9 - 14 V
+B (E5-1) @ Body groundInputEngine stopped, ignition switch ON9 - 14 V
+B2 (E5-2) @ Body groundInputEngine stopped, ignition switch ON9 - 14 V
NG REPAIR OR REPLACE FUSE OR WIRE
HARNESS AND CONNECTOR
OK
Page 981 of 2572
A53766
E7
E8E9E6
E5
- DIAGNOSTICSMULTIPLEX COMMUNICATION SYSTEM
05-2069
2259 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
3 CHECK ECM
(a) Inspect the ECM (body ground).
NOTICE:
Do not disconnect the ECM connector. The inspection should be started from the backside of the
connector.
(1) Inspect the continuity between each terminal of the ECM connector and the body ground.
Standard:
Symbols (Terminal No.)In/OutputConditionSpecified Condition
E1 (E9-1 (*1), E7-1 (*2)) @
Body groundInputConstantContinuity
(*1) : 2AZ-FE
(*2) : 3MZ-FE
NG REPAIR OR REPLACE HARNESS AND
CONNECTOR
OK
REPLACE ECM
Page 982 of 2572

H43056H44106
B19
Buckle SW (Driver's Side)Airbag Sensor
Assy Center
LBE+ A16 G
111
3R
LBE- A166 19
2 A16
A16(*2)
(*2) (*1)
(*1)
*1: w/ Curtain Shield Airbag
*2: w/o Curtain Shield Airbag
- DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
05-1287
1477 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
DTC B0126/27 SEAT BELT BUCKLE SWITCH (LH)
MALFUNCTION
CIRCUIT DESCRIPTION
The seat belt buckle switch LH circuit consists of the airbag sensor assy center and the front seat inner belt
assy LH (seat belt buckle switch LH).
DTC B0126/27 is recorded when a malfunction is detected in the seat belt buckle switch LH circuit.
DTC No.DTC Detecting ConditionTrouble Area
B0126/27
Short circuit in front seat inner belt assy LH wire harness
(to B+)
Short circuit in front seat inner belt assy LH wire harness
(to ground)
Open circuit in LBE+ wire harness or LBE- wire harness
of front seat inner belt assy LH
Front seat inner belt assy LH malfunction
Airbag sensor assy center malfunction
Front seat inner belt assy LH (Seat belt buckle switch LH)
Airbag sensor assy center
Floor wire No.2
WIRING DIAGRAM
05IVB-01
Page 983 of 2572

C85269H10600C85273H41027
Airbag
Sensor
Assy
Center Front Seat Inner
Belt Assy LH
DTC B0126/27 DLC3
CG
TC
05-1288
- DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1478 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
INSPECTION PROCEDURE
1 CHECK DTC
(a) Turn the ignition switch to the ON position, and wait for at
least 60 seconds.
(b) Clear the DTCs stored in memory (see page 05-1215).
(c) Turn the ignition switch to the LOCK position.
(d) Turn the ignition switch to the ON position and wait for at
least 60 seconds.
(e) Check the DTCs (see page 05-1215).
OK:
DTC B0126/27 is not output.
HINT:
Codes other than code B0126/27 may be output at this time, but
they are not related to this check.
NG Go to step 2
OK
USE SIMULATION METHOD TO CHECK
2 CHECK CONNECTION OF CONNECTORS
(a) Turn the ignition switch to the LOCK position.
(b) Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
(c) Check that the connectors are properly connected to the airbag sensor assy center and the front seat
inner belt assy LH.
OK:
The connectors are connected.
NG CONNECT CONNECTORS, THEN GO TO STEP
1
OK
Page 984 of 2572

H43342
H42459H44468
LBE+Airbag
Sensor
Assy
Center A
B C DFloor Wire No.2
1LBE-
3
Front Seat Inner
Belt Assy LH
B19
Service Wire
A16
A16
(*2)(*1)
LBE-
LBE+
H42459
Airbag
Sensor
Assy
Center Floor Wire No.2
Front Seat Inner
Belt Assy LH
LBE+LBE-
LBE+LBE-A16
A16
(*2)(*1)
- DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
05-1289
1479 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
3 CHECK FLOOR WIRE NO.2(OPEN)
(a) Disconnect the connectors from the airbag sensor assy
center and the front seat inner belt assy LH.
(b) Using a service wire, connect B19-1 and B19-3 of con-
nector ºCº.
NOTICE:
Do not forcibly insert a service wire into the terminal of the
connector when connecting.
(c) Measure the resistance according to the value(s) in the
table below.
Standard:
w/ Curtain shield airbag (*1):
Tester connectionConditionSpecified condition
A16-19 (LBE+) -
A16-2 (LBE-)AlwaysBelow 1 W
w/o Curtain shield airbag (*2):
Tester connectionConditionSpecified condition
A16-1 1 (LBE+) -
A16-6 (LBE-)AlwaysBelow 1 W
NG REPAIR OR REPLACE FLOOR WIRE NO.2
OK
4 CHECK FLOOR WIRE NO.2(TO B+)
(a) Disconnect the service wire from connector ºCº.
(b) Connect the negative (-) terminal cable to the battery,
and wait for at least 2 seconds.
(c) Turn the ignition switch to the ON position.
(d) Measure the voltage according to the value(s) in the table
below.
Standard:
w/ Curtain shield airbag (*1):
Tester connectionConditionSpecified condition
A16-19 (LBE+) -
Body groundIgnition switch ONBelow 1 V
A16-2 (LBE-) -
Body groundIgnition switch ONBelow 1 V
w/o Curtain shield airbag (*2):
Tester connectionConditionSpecified condition
A16-1 1 (LBE+) -
Body groundIgnition switch ONBelow 1 V
A16-6 (LBE-) -
Body groundIgnition switch ONBelow 1 V
NG REPAIR OR REPLACE FLOOR WIRE NO.2
OK