Page 2473 of 4323
I28483
Radio and Navigation Assy
R±W 1
7
R28 MUTE
MUTE Stereo Component
Amplifier Assy
S10
± DIAGNOSTICSNAVIGATION SYSTEM
DI±2271
2465 Author: Date:
2005 SEQUOIA (RM1146U)
Amplifier mute signal circuit
CIRCUIT DESCRIPTION
This circuit sends a signal to the stereo component amplifier to mute noise. Because of that, the noise pro-
duced by changing the sound source ceases.
If there is an open in the circuit, noise can be heard from the speakers when changing the sound source.
If there is a short in the circuit, even though the stereo component amplifier assy is normal, no sound or only
an extremely small sound can be produced.
WIRING DIAGRAM
DIDDI±01
Page 2474 of 4323

I28755
Stereo Component Amplifier Assy
Wire Harness View:
MUTES10
I28292MUTE
Radio and Navigation Assy
Wire Harness View:
R28
I28752
Stereo Component Amplifier Assy
Wire Harness View:
MUTE
S10
DI±2272
± DIAGNOSTICSNAVIGATION SYSTEM
2466 Author: Date:
2005 SEQUOIA (RM1146U)
INSPECTION PROCEDURE
1 Inspect stereo component amplifier assy.
PREPARATION:
Make sure that the stereo component amplifier assy connector
is connected.
CHECK:
Measure the voltage according to the value in the table below.
OK:
Symbol
(Tester connection)ConditionSpecification
MUTE (S10±1) ±
Body groundTurn ignition switch to
ACC, Audio system is
playing "Changing mode
Above 3.5 V " Below 1 V
OK Proceed to next circuit inspection shown in
problem symptoms table (See page DI±2184).
NG
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 values in the table be-
low.
OK:
Symbol
(Tester connection)ConditionSpecified condition
MUTE (R28±7) ±
MUTE (S10±1)AlwaysBelow 1 W
MUTE (R28±7) ±
Body groundAlways10 kW or higher
NG Repair or replace harness or connector.
OK
Page 2475 of 4323
I28746
Wire Harness View:
R28
MUTE
± DIAGNOSTICSNAVIGATION SYSTEM
DI±2273
2467 Author: Date:
2005 SEQUOIA (RM1146U)
3 Inspect radio and navigation assy.
PREPARATION:
Reconnect 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
MUTE (R28±7) ±
Body groundIgnition switch ONAbove 3.5 V
OK Replace stereo component amplifier assy.
NG
Replace radio and navigation assy.
Page 2476 of 4323
I28484
WRadio and
Navigation Assy
G 429
8
R BR30L+
L± Stereo Component
Amplifier Assy
R+
R±
SLD 19
18
10 3
S10
5
(Shielded) L+
L± R+
R±S10
S10
S10
S106
SGNDR30
R30
R30
R30 DI±2274
± DIAGNOSTICSNAVIGATION SYSTEM
2468 Author: Date:
2005 SEQUOIA (RM1146U)
Amplifier sound signal circuit
CIRCUIT DESCRIPTION
The radio receiver assy sends a sound signal to the stereo component amplifier assy through this circuit.
The sound signal that has been sent is amplified by the stereo component amplifier assy, and then sent to
the speakers.
If there is an open or short in the circuit, sound cannot be heard from the speakers even if there is no malfunc-
tion in the stereo component amplifier assy or the speakers.
WIRING DIAGRAM
DIDDJ±01
Page 2477 of 4323

I28292
L+
R± L±R+
R30
Radio and Navigation Assy
Wire Harness View:
I28752
S10
Stereo Component Amplifier Assy
Wire Harness View:
L+
R±L±
R+
± DIAGNOSTICSNAVIGATION SYSTEM
DI±2275
2469 Author: Date:
2005 SEQUOIA (RM1146U)
INSPECTION PROCEDURE
1 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 values in the table be-
low.
OK:
Symbol (Tester connection)Specified condition
L+ (R30±9) ± L+ (S10±3)Below 1 W
L± (R30±19) ± L± (S10±2)Below 1 W
R+ (R30±8) ± R+ (S10±5)Below 1 W
R± (R30±18) ± R± (S10±4)Below 1 W
L+ (R30±9) ± Body ground10 kW or higher
L± (R30±19) ± Body ground10 kW or higher
R+ (R30±8) ± Body ground10 kW or higher
R± (R30±18) ± Body ground10 kW or higher
NG Repair or replace harness or connector.
OK
Proceed to next circuit inspection shown in problem symptoms table (See page DI±2184).
Page 2478 of 4323
I28478
Stereo Component
Amplifier Assy
IB1 S9
T12
Tweeter LH F14
Front Door Speaker
and Woofer LH
IB1 IB1
IB1
S9S9
S9 WFL+
FL± WFL±
FL+
112 6 1712
2
3 4 23
41
5 4 67
1R G
L±W
L
VP L±W S1023
22
S10 INT+
INT±
G
VP11
13 R27 W
B
(Shielded)Radio and Navigation Assy
IVO+
IVO±
SLD1 R27
R27 DI±2276
± DIAGNOSTICSNAVIGATION SYSTEM
2470 Author: Date:
2005 SEQUOIA (RM1146U)
Speaker circuit (Navigation voice)
CIRCUIT DESCRIPTION
This circuit is used when the voice guidance in the radio and navigation assy is on.
Voice guidance of the navigation system is heard from the front door speaker LH via the tweeter LH.
WIRING DIAGRAM
DIDDL±01
Page 2479 of 4323
I28759
Connector Front View:
F14
± DIAGNOSTICSNAVIGATION SYSTEM
DI±2277
2471 Author: Date:
2005 SEQUOIA (RM1146U)
INSPECTION PROCEDURE
1 Inspect apparatus.
CHECK:
Choose the apparatus to be inspected.
RESULT:
ApparatusGo to step
Front door speaker LHA
Front door speaker LH and tweeter LHB
B Go to step 5.
A
2 Inspect front door speaker assy.
PREPARATION:
Disconnect the speaker connector.
CHECK:
Measure the resistance between the terminals of the speaker.
NOTICE:
The speaker should not be removed for checking.
OK:
Tester connectionSpecified condition
1 ± 2Approx. 3.15 W
3 ± 4Approx. 2.78 W
NG Replace front door speaker.
OK
Page 2480 of 4323

I28757
F14 Front Door Speaker
Connector Front View:
I28758
T12 Tweeter Connector front View:
DI±2278
± DIAGNOSTICSNAVIGATION SYSTEM
2472 Author: Date:
2005 SEQUOIA (RM1146U)
3 Inspect tweeter.
CHECK:
Check that the malfunction disappears when another tweeter in 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 with the left one.
OK Replace tweeter.
NG
4 Check harness and connector (Front door speaker ± tweeter).
CHECK:
Measure the resistance according to the value(s) in the table
below.
OK:
Tester connectionConditionSpecified condition
F14±1 ± T12±3AlwaysBelow 1 W
F14±2 ± T12±4AlwaysBelow 1 W
F14±1 ± Body groundAlways10 kW or higher
F14±2 ± Body groundAlways10 kW or higher
NG Repair or replace harness or connector.
NG
Proceed to next circuit inspection shown on problem symptoms table (See page DI±2184).