Page 1569 of 2572
I39187
Gateway ECU
Center J/B
Instrument Panel J/B
Passenger Side J/B
Instrument Panel J/B I15
IGNITION SW
F7
FL Block
Engine Room J/B
Center J/BIG
ACC
BATT
GNDCG RAD No.2IG1
ACC
IG1 AM1AM1
ALT
D.C.C
DOME
IB Battery FL MAINW-B W-B
W-B W
3F 13
3G6 3G5
G5 14G57 2A3
2I1
3 12 W43
2W
1C6
2
11A1V
IK312
V
4H6
4D11
V
IL211
LG L G
1C2 1C7
1J6 1K 10
W GR
3F9 3A8 3A 10
3F8 3D1 3I1
LG SBB
G58 G59 G52
B 05-1834
- DIAGNOSTICSNAVIGATION SYSTEM
2024 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
POWER SOURCE CIRCUIT (GATEWAY ECU)
CIRCUIT DESCRIPTION
This circuit provides power to the gateway ECU.
WIRING DIAGRAM
05ISY-02
Page 1570 of 2572
I40180
G5
CG
GNDIG
BATT
ACC
- DIAGNOSTICSNAVIGATION SYSTEM
05-1835
2025 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
INSPECTION PROCEDURE
1 INSPECT GATEWAY ECU(BATT, ACC, IG, GND ,CG)
(a) Disconnect the gateway ECU connector G5.
(b) Measure the resistance according to the value(s) in the
table below.
Standard:
Tester connectionConditionSpecified condition
GND - Body groundAlwaysBelow 1 W
CG - Body groundAlwaysBelow 1 W
(c) Measure the voltage according to the value(s) in the table
below.
Standard:
Tester connectionConditionSpecified condition
BATT - GND or CGAlways10 to 14 V
ACC - GND or CGIgnition SW ACC10 to 14 V
IG - GND or CGIgnition SW ON10 to 14 V
NG REPAIR OR REPLACE HARNESS OR
CONNECTOR
OK
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN DIAGNOSTIC TROUBLE CODE CHART
(SEE PAGE 05-1791)
Page 1571 of 2572
I39189
Navigation ECU
Center J/B Instrument Panel J/B
Passenger Side J/B
Instrument Panel J/B I15
IGNITION SW
F7
FL Block
Engine Room J/B
Center J/BACC
+B
GND1
IB
Battery FL MAINALT
D.C.C
DOME ACC AM1AM1 RAD No.2
W-B W-BV
W WBW LV V LGW GR V
N317
3I2
3F132A3
2I1 2
1321C6
211A1IK312
4H6
4D 11
IL211 1C2
1K3
3F9 3A13
3I7 3I 10
N39 N3 18
3 05-1830
- DIAGNOSTICSNAVIGATION SYSTEM
2020 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
POWER SOURCE CIRCUIT (NAVIGATION ECU)
CIRCUIT DESCRIPTION
This circuit provides power to the navigation ECU.
WIRING DIAGRAM
05CEG-08
Page 1572 of 2572
I40178
N3
+B
ACC
GND1
- DIAGNOSTICSNAVIGATION SYSTEM
05-1831
2021 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
INSPECTION PROCEDURE
1 INSPECT NAVIGATION ECU(+B, ACC, GND1)
(a) Disconnect the navigation ECU connector N3.
(b) Measure the resistance according to the value(s) in the
table below.
Standard:
Tester connectionConditionSpecified condition
GND1 - Body groundAlwaysBelow 1 W
(c) Measure the voltage according to the value(s) in the table
below.
Standard:
Tester connectionConditionSpecified condition
+B - GND1Always10 to 14 V
ACC - GND1Ignition SW ACC10 to 14 V
NG REPAIR OR REPLACE HARNESS OR
CONNECTOR
OK
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE OR
DIAGNOSTIC TROUBLE CODE CHART (SEE PAGE 05-1778 OR 05-1791)
Page 1573 of 2572
I39199
Multi-display Controller Sub-assy Radio Receiver Assy
TX1+
TX1- TX+
TX-
R2930 R2931
GRLG
IP1 19IP19
L Y
R2310 R239
(*1) (*1)
(*1) (*1)
*1: w/ Rear Seat Entertainment System 05-1688
- DIAGNOSTICSAUDIO SYSTEM
1878 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
AVC-LAN CIRCUIT (MULTI-DISPLA Y CONTROLLER SUB-ASSY -
RADIO RECEIVER ASSY
CIRCUIT DESCRIPTION
Each unit of the radio receiver system connected to AVC-LAN (communication bus) communicates by trans-
ferring the signals from each switch.
When +B short and GND short occur in this AVC-LAN, radio receiver system will not function normally as
communication is discontinued.
In AVC-LAN, radio receiver assy becomes the communication master, and the radio receiver assy has
enough resistance necessary for transmitting the communication.
WIRING DIAGRAM
05IRU-02
Page 1574 of 2572

I40222
TX1+ TX1-
R23
I34639
Multi-display Controller Sub-assy:
R29
TX+TX-
I40203
Radio Receive Assy:
R23
TX1+
TX1-
- DIAGNOSTICSAUDIO SYSTEM
05-1689
1879 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
INSPECTION PROCEDURE
1 INSPECT RADIO RECEIVER ASSY
(a) Measure the resistance according to the value(s) in the
table below.
Standard:
Tester connectionConditionSpecified condition
TX1+ - TX1-Always60 to 80 W
NG REPLACE RADIO RECEIVER ASSY
(SEE PAGE 67-6)
OK
2 CHECK HARNESS AND CONNECTOR(MULTI-DISPLA Y CONTROLLER
SUB-ASSY - RADIO RECEIVER ASSY)
(a) Disconnect the connectors from the multi-display control-
ler sub-assy R29 and radio receiver assy R23.
(b) Measure the resistance according to the value(s) in the
table below.
Standard:
Tester connectionConditionSpecified condition
TX+ - TX1+AlwaysBelow 1 W
TX- - TX1-AlwaysBelow 1 W
TX+ - Body groundAlways10 kW or higher
TX- - Body groundAlways10 kW or higher
NG REPAIR OR REPLACE HARNESS OR
CONNECTOR
OK
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
(SEE PAGE 05-1632)
Page 1575 of 2572
05-1854
- DIAGNOSTICSNAVIGATION SYSTEM
2044 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
DIMMER SIGNAL CIRCUIT
CIRCUIT DESCRIPTION
When the light control switch is in the TAIL or HEAD position, the TAILLIGHT relay activates and supplies
power to illuminate the multi-display panel.
05IT5-02
Page 1576 of 2572
I40219
Multi-display Assy Center J/B C11
Combination Meter
Taillight System
F7
FL BlockILL-
ILL+ 3F5
3F9
3F13 3F3
3D3
3E 10
3A12
3I4
1 6
37
11
1222B
G
ORV
W
1A
1J 1K2A 2I4D 4HPassenger Side J/B
Engine Room J/B
Instrument Panel J/B
BB2
1 12
11
7
3
5
211LGM3
M3
IL2 IK3W-B
W-B
2
3 1
WALTDOME D.C.C
TAILLIGHT Relay PANEL
FL MAIN
Battery
IB V
4V
- DIAGNOSTICSNAVIGATION SYSTEM
05-1855
2045 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
WIRING DIAGRAM