Toyota Sequoia (2005). Manual - part 619

I28483

Radio and Navigation Assy

R–W

1

7

R28

MUTE

MUTE

Stereo Component 
Amplifier Assy

S10

–

DIAGNOSTICS

NAVIGATION SYSTEM

DI–2271

2465

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

I28755

Stereo Component Amplifier Assy
Wire Harness View:

MUTE

S10

I28292

MUTE

Radio and Navigation Assy 
Wire Harness View:

R28

I28752

Stereo Component Amplifier Assy
Wire Harness View:

MUTE

S10

DI–2272

–

DIAGNOSTICS

NAVIGATION SYSTEM

2466

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)

Condition

Specification

MUTE (S10–1) –

Body ground

Turn 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)

Condition

Specified condition

MUTE (R28–7) – 

MUTE (S10–1)

Always

Below 1 

Ω

MUTE (R28–7) – 

Body ground

Always

10 k

Ω 

or higher

NG

Repair or replace harness or connector.

OK

I28746

Wire Harness View:

R28

MUTE

–

DIAGNOSTICS

NAVIGATION SYSTEM

DI–2273

2467

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)

Condition

Specified condition

MUTE (R28–7) – 

Body ground

Ignition switch ON

Above 3.5 V

OK

Replace stereo component amplifier assy.

NG

Replace radio and navigation assy.

I28484

W

Radio and 
Navigation Assy

G

4

2

9

8

R

B

R30 L+

L–

Stereo Component 
Amplifier Assy

R+

R–

SLD

19

18

10

3

S10

5

(Shielded)

L+

L–

R+

R–

S10

S10

S10

S10

6

SGND

R30

R30

R30

R30

DI–2274

–

DIAGNOSTICS

NAVIGATION SYSTEM

2468

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