TOYOTA SEQUOIA 2001 Service Repair Manual

I28324
ACC
EB+
B2+
GND
S10S9
± DIAGNOSTICSNAVIGATION SYSTEM
DI±2259
2453 Author: Date:
2005 SEQUOIA (RM1146U)
INSPECTION PROCEDURE
1 Inspect stereo component amplifier assy (B+, B2+, ACC, GND, E).
PREPARATION:
Disconnect the stereo component amplifier assy connectors.
CHECK:
Measure the resistance according to the value(s) in the table
below.
OK:
Symbol
(Tester connection)ConditionSpecified condition
E (S9±16) ± Body groundAlwaysBelow 1 W
GND (S9±15) ±
Body groundAlwaysBelow 1 W
CHECK:
Measure the voltage according to the value(s) in the table be-
low.
OK:
Symbol
(Tester connection)ConditionSpecified condition
B+ (S9±1) ± GND (S9±15)Always10 to 14 V
B2+ (S9±10) ±
GND (S9±15)Always10 to 14 V
ACC (S10±12) ±
GND (S9±15)Ignition 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 DI±2203 or DI±2184).

I28766
R6
Light Control
Rheostat AssyRadio and Navigation Assy
J/C
Steering Pad Switch Assy
Spiral Cable
Sub±assy From
TAILLIGHT
RelayILL±
SWG J/C
ILL+ W±G
GJ39 J40
J39 J40
J39 J40W±G
G
G
G A B
A
AAB
ILL±
T12
2
6 1
10C9±1
BR±W
C9±10 6
4
Steering SWR30
R27 R30 DI±2260
± DIAGNOSTICSNAVIGATION SYSTEM
2454 Author: Date:
2005 SEQUOIA (RM1146U)
Illumination circuit
CIRCUIT DESCRIPTION
Power is supplied to the radio and navigation panel illumination when the light control switch is in the TAIL
or HEAD position. The body ECU determines the external brightness based on the brightness level detected
by the automatic light control sensor, and then operates the TAILLIGHT relay. Power can also be supplied
by operating the relay.
The intensity of the radio receiver panel illumination can be adjusted by the rheostat switch.
WIRING DIAGRAM
DIDDF±01

± DIAGNOSTICSNAVIGATION SYSTEM
DI±2261
2455 Author: Date:
2005 SEQUOIA (RM1146U)
INSPECTION PROCEDURE
NOTICE:
The vehicle is equipped with SRS (Supplemental Restraint System) such as airbags. Before servic-
ing (including removal or installation of parts), be sure to read the precautionary notice for the sup-
plemental restraint system (See page RS±1).
1 Check illumination.
CHECK:
Check if the illumination for the radio and navigation assy, steering pad switch assy or others (A/C switch,
cigarette lighter, etc.) comes on when the light control switch is turned to the HEAD or TAIL position.
RESULT:
Components with illuminationGo to step
Illumination comes on for all components except radio and navigation assy.A
Illumination comes on for all components except steering pad switch.B
Illumination comes on for all components except radio and navigation assy,
steering pad switch, Rear heater control panel, each switch, etc.C
All illumination does not come on. (Radio and navigation assy, steering pad
switch, Combination meter, Rear heater control panel, each switch, etc.)D
HINT:
If the illuminations have malfunctions, check the rheostat switch.
B Go to step 4.
C Go to step 8.
D Go to combination meter system
(See page DI±1645).
A

I28747
R30
ILL+
DI±2262
± DIAGNOSTICSNAVIGATION SYSTEM
2456 Author: Date:
2005 SEQUOIA (RM1146U)
2 Check radio and navigation assy (ILL+).
PREPARATION:
Disconnect the radio and navigation assy connector.
CHECK:
Measure the voltage according to the value(s) in the table be-
low.
OK:
Symbol
(Tester connection)ConditionSpecified condition
ILL+ (R30±2) ±
Body groundLight control switch TAIL10 to 14 V
NG Repair or replace wire harness or connector
(Radio and navigation assy ± battery).
OK

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

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

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

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

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.

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