Page 1585 of 2572
I34965
Radio Receiver Assy Multi-Display
TX+
TX- TX+
TX-
R2210 R229
O LG
M414 M413
*1
*1
*1: w/o Rear Seat Entertainment System 05-1866
- DIAGNOSTICSNAVIGATION SYSTEM
2056 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
AVC-LAN CIRCUIT (RADIO RECEIVER ASSY - MULTI-DISPLA Y)
CIRCUIT DESCRIPTION
Each unit of the navigation system connected to AVC-LAN (communication bus) communicates by transfer-
ring the signals from each switch.
When +B short and GND short occur in this AVC-LAN, navigation system will not function normally as com-
munication is discontinued.
In AVC-LAN, multi-display becomes the communication master, and the radio receiver assy has enough
resistance necessary for transmitting the communication.
WIRING DIAGRAM
05ITA-02
Page 1586 of 2572
I40221
TX-
TX+
R22
I40185
Radio Receiver Assy:
R22
TX-TX+
I38998
Multi-Display:
TX-TX+
M4
- DIAGNOSTICSNAVIGATION SYSTEM
05-1867
2057 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
TX+ - TX-Always60 to 80 W
NG REPLACE RADIO RECEIVER ASSY
(SEE PAGE 67-6)
OK
2 CHECK HARNESS AND CONNECTOR(RADIO RECEIVER ASSY -
MULTI-DISPLA Y)
(a) Disconnect the connector from the radio receiver assy
and multi-display.
(b) Measure the resistance according to the value(s) in the
table below.
Standard:
Tester connectionConditionSpecified condition
TX+ - TX+AlwaysBelow 1 W
TX- - TX-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 DIAGNOSTIC TROUBLE CODE CHART
(SEE PAGE 05-1791)
Page 1587 of 2572
I40199
FL+ Stereo Component
Amplifier AssyNavigation ECU
T11
Front No.2 speaker
Assy LH FL-S23
S239 2
Y
R-Y10
IR1
IR1
7
IB1
IB16 F10
Front No.1
Speaker Assy
LHP
VP
GIF3
IF310
20G
BN3
N32
11AUI+
AUI-
AUO+
AUO- LG
RN3
N3 101
R
W 1
23
41
220(*1)
(*1)
(*1)
(*1)
*1: w/ Navigation System 05-1664
- DIAGNOSTICSAUDIO SYSTEM
1854 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
SPEAKER CIRCUIT (DRIVER SIDE SPEAKER)
CIRCUIT DESCRIPTION
When the vehicle is equipped with the navigation system, a sound signal for the driver's side is sent from
the stereo component amplifier to the driver's side speaker via the navigation ECU.
WIRING DIAGRAM
05IRR-02
Page 1588 of 2572
- DIAGNOSTICSAUDIO SYSTEM
05-1665
1855 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
INSPECTION PROCEDURE
1 CHECK NAVIGATION VOICE GUIDANCE
(a) Check if navigation voice guidance is heard from the speaker on the driver side.
OK: Voice guidance is heard.
OK Go to step 8
NG
2 CHECK SETTING(THE VOLUME OF THE NAVIGATION VOICE SOUND)
(a) Check that ºOFFº is not selected.
OK: OFF is not selected.
NG USING VOICE ADJUSTMENT SWITCH, TURN
THE VOICE GUIDANCE VOLUME UP
OK
3 INSPECT SYSTEM
(a) Check the system.
(1) Check if sound is heard from speakers.
SymptomProceed to
No sound is heard from both speakersA
No sound is heard from front No.1 speaker assyB
No sound is heard from front No.2 speaker assyReplace front No.2 speaker assy (see page 67-1 1)
B Go to step 6
A
Page 1589 of 2572

I40178I38999I40553
Navigation ECU:
Wire Harness Side:
Front No.2 Speaker AssyN3
AUO+
AUO-
05-1666
- DIAGNOSTICSAUDIO SYSTEM
1856 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
4 CHECK HARNESS AND CONNECTOR(NAVIGATION ECU - FRONT NO. 2
SPEAKER ASSY)
(a) Disconnect the connectors from the navigation ECU and
speaker.
(b) Measure the resistance according to the values in the
table below.
Standard:
Tester connectionConditionSpecified condition
AUO+ - 1AlwaysBelow 1 W
AUO- - 2AlwaysBelow 1 W
AUO+ - Body groundAlways10 kW or higher
AUO- - Body groundAlways10 kW or higher
NG REPAIR OR REPLACE HARNESS OR
CONNECTOR
OK
5 INSPECT FRONT NO. 2 SPEAKER ASSY
(a) Check that malfunction disappears when another speaker in a good condition is installed.
OK: Malfunction disappears.
HINT:
Connect all the connectors to the speakers.
When there is a possibility that either right or left front speaker is defective, inspect by interchanging
the right one and the left one.
OK REPLACE FRONT NO. 2 SPEAKER ASSY
(SEE PAGE 67-1 1)
NG
Page 1590 of 2572

I38999I38233I40554
Wire Harness Side:
Front No.1 Speaker Assy Wire Harness Side:
Front No.2 Speaker Assy
- DIAGNOSTICSAUDIO SYSTEM
05-1667
1857 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
6 CHECK HARNESS AND CONNECTOR(FRONT NO. 2 SPEAKER ASSY - FRONT
NO. 1 SPEAKER ASSY)
(a) Disconnect the connectors from the front No.2 speaker
assy and front No.1 speaker assy.
(b) Measure the resistance according to the values in the
table below.
Tester connectionConditionSpecified condition
3 (Front No.2 speaker
Assy) - 1 (Front No.1
speaker Assy)
AlwaysBelow 1 W
4 (Front No.2 speaker
Assy) - 2 (Front No.1
speaker Assy)
AlwaysBelow 1 W
3 (Front No.2 speaker
Assy) - Body groundAlways10 kW or higher
4 (Front No.2 speaker
Assy) - Body groundAlways10 kW or higher
NG REPAIR OR REPLACE HARNESS OR
CONNECTOR
OK
7 INSPECT FRONT NO. 1 SPEAKER ASSY
(a) Resistance check
(1) Measure the resistance between the terminals of the speaker.
NOTICE:
The speaker should not be removed for checking.
Standard: 4 W
NG REPLACE FRONT NO. 1 SPEAKER ASSY
(SEE PAGE 67-10)
OK
REPLACE NAVIGATION ECU (SEE PAGE 67-9)
Page 1591 of 2572

I40178I39179I40555
Navigation ECU:
Stereo Component Amplifier Assy:N3
AUI+
AUI-
S23
FL+
FL-
I40178
N3
AUI+
AUI-AUO+
AUO-
05-1668
- DIAGNOSTICSAUDIO SYSTEM
1858 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
8 CHECK HARNESS AND CONNECTOR(NAVIGATION ECU - STEREO COMPONENT
AMPLIFIER ASSY)
(a) Disconnect the connectors from the navigation ECU and
stereo component amplifier assy.
(b) Measure the resistance according to the values in the
table below.
Standard:
Tester connectionConditionSpecified condition
AUI+ - FL+AlwaysBelow 1 W
AUI- - FL-AlwaysBelow 1 W
AUI+ - Body groundAlways10 kW or higher
AUI- - Body groundAlways10 kW or higher
NG REPAIR OR REPLACE HARNESS OR
CONNECTOR
OK
9 INSPECT NAVIGATION ECU
(a) Disconnect the connector from the navigation ECU.
(b) Measure the resistance according to the values in the
table below.
Standard:
Tester connectionConditionSpecified condition
AUI+ - AUO+AlwaysBelow 1 W
AUI- - AUO-AlwaysBelow 1 W
NG REPLACE NAVIGATION ECU
(SEE PAGE 67-9)
OK
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
(SEE PAGE 05-1632)
Page 1592 of 2572
I39188
Multi-Display
Center J/B Instrument Panel J/B
Engine Room R/B
Instrument Panel J/B I15
IGNITION SW
F7
FL Block
Center J/BIG
ACC
+B1
GND1
Battery FL MAINALTRAD No.2ECU-IG
W-B W-B
IB W
WB IG1 AM1 ACC
WAM1 CRT
VVJ17
J/C
VVBRO
V R
M3 10
M311
M3 12 3E3 3G7
3A 13 3A1
1K3 1K9
1C2 1C7
L G
IK2 16
A
AIL16
2
1 2 2
42 3
1C6
211A1
1
3 2
3F13
3I6
M33 05-1828
- DIAGNOSTICSNAVIGATION SYSTEM
2018 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
POWER SOURCE CIRCUIT (MULTI-DISPLA Y)
CIRCUIT DESCRIPTION
This circuit provides power to the multi-display.
WIRING DIAGRAM
05CEF-10