Page 2465 of 4323

I28747
Radio and Navigation Assy
Wire Harness View:
R30
ILL±
I28577
R6 Light Control Rheostat
Wire Harness View:
ILL±
I28750
R27
SWG
Wire Harness View:
± DIAGNOSTICSNAVIGATION SYSTEM
DI±2263
2457 Author: Date:
2005 SEQUOIA (RM1146U)
3 Check harness and connector (Radio and navigation assy ± light control rheo-
stat).
PREPARATION:
Disconnect the radio and navigation assy and light control rheo-
stat connectors.
CHECK:
Measure the resistance according to the value(s) in the table
below.
OK:
Symbol
(Tester connection)ConditionSpecified condition
ILL± (R30±12) ±
ILL± (R6±6)AlwaysBelow 1 W
ILL± (R30±12) ±
Body groundAlways10 kW or higher
NG Repair or replace wire harness or connector.
OK
Replace radio and navigation assy.
4 Check radio and navigation assy.
PREPARATION:
Disconnect the radio and navigation assy connector.
CHECK:
Measure the voltage according to the value(s) in the table be-
low.
OK:
Symptom
(Tester connection)ConditionSpecified condition
SWG (R27±6) ±
Body groundLight control switch TAIL10 to 14 V
OK Replace radio and navigation assy.
NG
Page 2466 of 4323
I28296
1
10
DI±2264
± DIAGNOSTICSNAVIGATION SYSTEM
2458 Author: Date:
2005 SEQUOIA (RM1146U)
5 Inspect steering pad switch assy.
PREPARATION:
(a) Disconnect the steering pad switch connector.
(b) Connect the positive (+) lead to terminal 1 and the negative (±) lead to terminal 10 of steering pad
switch assy connector.
CHECK:
Check if the illumination for the steering pad switch assy comes on.
OK:
Illumination for the steering pad switch assy comes on.
NG Replace steering pad switch assy.
OK
Page 2467 of 4323
I28295
Vehicle Side:
Steering Pad Switch Assy Side:
C9
± DIAGNOSTICSNAVIGATION SYSTEM
DI±2265
2459 Author: Date:
2005 SEQUOIA (RM1146U)
6 Inspect spiral cable sub±assy.
PREPARATION:
Remove the spiral cable sub±assy.
CHECK:
Measure the resistance according to the value(s) in the table
below.
OK:
Tester connectionConditionSpecified condition
C9±1 ± 1AlwaysBelow 1 W
C9±10 ± 10AlwaysBelow 1 W
NG Replace spiral cable sub±assy.
OK
Page 2468 of 4323

I28750
Radio and Navigation Assy
Wire Harness View:
R27
SWG
I28294
Spiral Cable Sub±assy
Connector Front View:
C9
I28576
270°
Bright
0°
DarkR6
ILL±
DI±2266
± DIAGNOSTICSNAVIGATION SYSTEM
2460 Author: Date:
2005 SEQUOIA (RM1146U)
7 Check harness and connector (Radio and navigation assy ± spiral cable sub±
assy).
PREPARATION:
Disconnect the spiral cable sub±assy and radio and navigation
assy connectors.
CHECK:
Measure the resistance according to the value(s) in the table
below.
OK:
Symbol
(Tester connection)ConditionSpecified condition
SWG (R27±6) ±
Spiral cable terminal 10AlwaysBelow 1 W
SWG (R27±6) ±
Body groundAlways10 kW or higher
NG Repair or replace wire harness or connector
(Radio and navigation assy ± spiral cable sub±
assy).
OK
Repair or replace wire harness or connector (Battery ± spiral cable sub±assy).
8 Inspect light control rheostat.
PREPARATION:
(a) Reconnect the light control rheostat switch connector.
(b) Ignition switch is ON.
(c) Light control switch is TAIL or HEAD.
CHECK:
Measure the voltage according to the value(s) in the table be-
low.
OK:
Symbol
(Tester connection)ConditionSpecified condition
ILL± (R6±6) ±
Body groundRheostat knob to fully
counterclockwise "
fully clockwise
Below 1 V " 10 to 14 V
Page 2469 of 4323
I28747
Radio and Navigation Assy
Wire Harness View:
R30
ILL±
I28577
R6 Light Control Rheostat
Wire Harness View:
ILL±
± DIAGNOSTICSNAVIGATION SYSTEM
DI±2267
2461 Author: Date:
2005 SEQUOIA (RM1146U)
NG Replace light control rheostat.
OK
9 Check harness and connector (Radio and navigation assy ± light control rheo-
stat).
PREPARATION:
Disconnect the radio and navigation assy connector.
CHECK:
Measure the resistance according to the value(s) in the table
below.
OK:
Symbol
(Tester connection)ConditionSpecified condition
ILL± (R30±12) ±
ILL± (R6±6)AlwaysBelow 1 W
ILL± (R30±12) ±
Body groundAlways10 kW or higher
NG Repair or replace wire harness or connector.
OK
Replace radio and navigation assy.
Page 2470 of 4323
I28482
Stereo Component
Amplifier Assy
Radio and Navigation Assy
TX+
S10 R30V
P
TX±
S10ATX+
ATX± 20 5
19 15
R30 DI±2268
± DIAGNOSTICSNAVIGATION SYSTEM
2462 Author: Date:
2005 SEQUOIA (RM1146U)
AVC±LAN circuit (Radio and navigation assy ± stereo component
amplifier assy)
CIRCUIT DESCRIPTION
Each unit of the audio system connected to the AVC±LAN (communication bus) transfers the signal of each
switch by communication.
When a short to +B or short to ground occurs in this AVC± LAN, the audio system will not function normally
as communication is discontinued.
In this AVC±LAN, the radio and navigation assy becomes the master of the communication and the has re-
sistance necessary for communication.
WIRING DIAGRAM
DIDDH±01
Page 2471 of 4323

I28747
Radio and Navigation Assy
Wire Harness View:
ATX+
ATX±
R30
I28752TX+TX±
S10
Stereo Component Amplifier Assy
Wire Harness View:
± DIAGNOSTICSNAVIGATION SYSTEM
DI±2269
2463 Author: Date:
2005 SEQUOIA (RM1146U)
INSPECTION PROCEDURE
1 Service check mode (Stereo component amplifier assy).
CHECK:
Start the diagnostic system and read the check result for the stereo component amplifier assy (See page
DI±2191).
RESULT:
ºNCONº is displayed or result is not displayed (DSP AMP)Go to step A
ºGOODº is displayedGo to step B
B Proceed to next circuit inspection shown in
problem symptoms table or diagnostic trouble
code chart (See page DI±2184 or DI±2203)
A
2 Check harness and connector (Radio and navigation assy ± stereo component
amplifier assy).
PREPARATION:
Disconnect the radio and navigation assy and stereo compo-
nent amplifier assy connectors.
CHECK:
Measure the resistance according to the value(s) in the table
below.
OK:
Symbol
(Tester connection)ConditionSpecified condition
ATX+ (R30±5) ±
TX+ (S10±20)AlwaysBelow 1 W
ATX± (R30±15) ±
TX± (S10±19)AlwaysBelow 1 W
ATX+ (R30±5) ±
Body groundAlways10 kW or higher
ATX± (R30±15) ±
Body groundAlways10 kW or higher
NG Repair or replace harness or connector.
OK
Page 2472 of 4323
DI±2270
± DIAGNOSTICSNAVIGATION SYSTEM
2464 Author: Date:
2005 SEQUOIA (RM1146U)
Replace stereo component amplifier assy.