Page 969 of 2572
E74075
Body ECU
C13
Combination Switch
Light
Control
SwitchTAIL
HEAD
OFF
Tail
HeadV
LG18
B10
17
B10
14 13
THEL
IA16
W-B 05-1548
- DIAGNOSTICSLIGHTING SYSTEM
1738 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
DTC B1241 BODY ECU SWITCH CIRCUIT DIAGNOSIS
CIRCUIT DESCRIPTION
The following explains when this DTC is output:
This DTC is not output when the switches are operated but fail to make contact. It is only output when the
switches are stuck or held on. For example, this code is output when checking the DTC while the switches
are on:
System is normal:
(a) DTC is output during DTC check with the switches on.
(b) DTC is not output during DTC check with the switches off.
Inspect the switches and replace if necessary. If there is no problem with the switches, inspect the wire har-
ness.
DTC No.DTC Detecting ConditionTrouble Area
B1241Switch is stuck
Headlamp dimmer switch assy
Wire harness or connector
Multiplex network body ECU
WIRING DIAGRAM
05IQ7-01
Page 970 of 2572

E11948
Connector Front View:
C13
- DIAGNOSTICSLIGHTING SYSTEM
05-1549
1739 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
INSPECTION PROCEDURE
1 READ VALUE OF HAND-HELD TESTER
(a) Connect the hand-held tester to the DLC3.
(b) Turn the ignition switch to the ON position and turn the hand-held tester main switch on.
(c) Select the item below in the DATA LIST and read the display on hand-held tester.
BODY NO.1 (MULTIPLEX NETWORK BODY ECU):
ItemMeasurement Item/
Display (Range)Normal ConditionDiagnostic Note
HEAD LIGHT SWHeadlight control
SW signal/ ON or OFFON: Light control switch is in HEAD position
OFF: Light control switch is in except HEAD position-
TAIL LIGHT SWTail light SW signal/
ON or OFFON: Light control switch is in TAIL position
OFF: Light control switch is in except TAIL position-
OK: Condition sign can be displayed.
NG Go to step 2
OK
REPLACE MULTIPLEX NETWORK BODY ECU
2 INSPECT HEADLAMP DIMMER SWITCH ASSY
(a) Inspect light control switch.
(1) Measure the resistance according to the value(s) in
the table below.
Standard:
Tester connectionConditionSpecified condition
14 - 16TAILBelow 1 W
13 - 16
14 - 16HEADBelow 1 W
NG REPLACE HEADLAMP DIMMER SWITCH ASSY
(SEE PAGE 65-25)
OK
Page 971 of 2572
E11948
Headlamp Dimmer Switch Connector
Front View:
C13
E74263
B10
B10-17
B10-18 Multiplex Network Body ECU
Connector Front View:
05-1550
- DIAGNOSTICSLIGHTING SYSTEM
1740 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
3 CHECK HARNESS AND CONNECTOR(HEADLAMP DIMMER SWITCH ASSY -
MULTIPLEX NETWORK BODY ECU)
(a) Disconnect the headlamp dimmer switch assy connector
and B10 connector from the multiplex network body ECU.
(b) Measure the resistance according to the value(s) in the
table below.
Standard:
Tester connectionConditionSpecified condition
C13-13 - B10-17AlwaysBelow 1 W
C13-14 - B10-18AlwaysBelow 1 W
B10-17 - Body groundAlways10 kW or higher
B10-18 - Body groundAlways10 kW or higher
C13-16 - Body groundAlwaysBelow 1 W
NG REPAIR OR REPLACE HARNESS OR
CONNECTOR
OK
REPLACE MULTIPLEX NETWORK BODY ECU
Page 972 of 2572
E68822E70389
4
3
1 A23
Automatic Light Control Sensor
21
20
12 B9
B9
B9CLTS
CLTE
CLTB R
W
GBody ECU
CLTS
CLTE
CLTB
- DIAGNOSTICSLIGHTING SYSTEM
05-1551
1741 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
DTC B1244 LIGHT SENSOR CIRCUIT MALFUNCTION
CIRCUIT DESCRIPTION
This DTC is output when a failure in the automatic light control sensor circuit is detected.
DTC No.DTC Detecting ConditionTrouble Area
B1244Malfunction of automatic light control sensorAutomatic light control sensor
Wi h tB1244Malfunction of automatic light control sensor
Open or short in automatic light control sensor circuitWire harness or connector
Multiplex network body ECU
WIRING DIAGRAM
05IQ8-01
Page 973 of 2572

I39976
Wire Harness View:
Automatic Light Control Sensor
A23
1 3
I39976
Wire Harness View:
Automatic Light Control Sensor
A23
4
E74263
B9
B9-21 Multiplex Network Body ECU
Connector Front View:
05-1552
- DIAGNOSTICSLIGHTING SYSTEM
1742 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
INSPECTION PROCEDURE
1 CHECK HARNESS AND CONNECTOR(AUTOMATIC LIGHT CONTROL SENSOR
POWER SOURCE CIRCUIT)
(a) Disconnect the automatic light control sensor connector.
(b) Measure the voltage according to the value(s) in the table
below.
Standard:
Tester connectionConditionSpecified condition
A23-1 - A23-3Ignition switch ON10 to 14 V
NG Go to step 4
OK
2 CHECK HARNESS AND CONNECTOR(MULTIPLEX NETWORK BODY ECU -
AUTOMATIC LIGHT CONTROL SENSOR)
(a) Disconnect the B9 connector from the multiplex network
body ECU.
(b) Measure the resistance according to the value(s) in the
table below.
Standard:
Tester connectionConditionSpecified condition
A23-4 - B9-21AlwaysBelow 1 W
NG REPAIR OR REPLACE HARNESS OR
CONNECTOR
OK
Page 974 of 2572
I39976
Wire Harness View:
Automatic Light Control Sensor
A23
1
- DIAGNOSTICSLIGHTING SYSTEM
05-1553
1743 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
3 REPLACE AUTOMATIC LIGHT CONTROL SENSOR
OK: Return to normal condition.
NG REPLACE MULTIPLEX NETWORK BODY ECU
OK
END
4 CHECK HARNESS AND CONNECTOR(MULTIPLEX NETWORK BODY ECU -
AUTOMATIC LIGHT CONTROL SENSOR)
(a) Measure the voltage according to the value(s) in the table
below.
Standard:
Tester connectionConditionSpecified condition
A23-1 - Body groundIgnition switch ON10 to 14 V
NG Go to step 6
OK
Page 975 of 2572
I39976
Wire Harness View:
Automatic Light Control Sensor
A23
3
E74263
B9
B9-20 Multiplex Network Body ECU
Connector Front View:
05-1554
- DIAGNOSTICSLIGHTING SYSTEM
1744 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
5 CHECK HARNESS AND CONNECTOR(MULTIPLEX NETWORK BODY ECU -
AUTOMATIC LIGHT CONTROL SENSOR)
(a) Disconnect the B9 connector from the multiplex network
body ECU.
(b) Measure the resistance according to the value(s) in the
table below.
Standard:
Tester connectionConditionSpecified condition
A23-3 - B9-20AlwaysBelow 1 W
NG REPAIR OR REPLACE HARNESS OR
CONNECTOR
OK
REPLACE MULTIPLEX NETWORK BODY ECU
Page 976 of 2572
I39976
Wire Harness View:
Automatic Light Control Sensor
A23
1
E74263
B9
B9-12 Multiplex Network Body ECU
Connector Front View:
- DIAGNOSTICSLIGHTING SYSTEM
05-1555
1745 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
6 CHECK HARNESS AND CONNECTOR(MULTIPLEX NETWORK BODY ECU -
AUTOMATIC LIGHT CONTROL SENSOR)
(a) Disconnect the B9 connector from the multiplex network
body ECU.
(b) Measure the resistance according to the value(s) in the
table below.
Standard:
Tester connectionConditionSpecified condition
A23-1 - B9-12AlwaysBelow 1 W
NG REPAIR OR REPLACE HARNESS OR
CONNECTOR
OK
REPLACE MULTIPLEX NETWORK BODY ECU