Toyota Sequoia (2005). Manual - part 588

I28598

Multi–display
Controller Sub–assy

LG

28

RMUT

IF3

16

R23

R–W

LG

12

LMUT

IF3

4

R23

R–G

RMU

MUTE

Radio Receiver Assy

19

R19

6

R20

w/o Navigation System:

I28598

Multi–display
Controller Sub–assy

LG

28

RMUT

IF3

16

R23

R–W

LG

12

LMUT

IF3

4

R23

R–G

RMUT

MUTE

Radio and Navigation Assy

19

R27

6

R28

w/ Navigation System:

–

DIAGNOSTICS

REAR SEAT ENTERTAINMANT SYSTEM

DI–2147

2341

Mute signal circuit (Radio receiver assy / Radio and navigation
assy – Multi–display controller sub–assy)

CIRCUIT DESCRIPTION

The multi–display controller sub–assy controls the volume according to the MUTE signal from the radio re-
ceiver assy or radio and navigation assy.
The MUTE signal is sent to reduce noise and a popping sound generated when the mode, etc. is switched.

WIRING DIAGRAM

DIDBK–01

I28610

RMUT

R23

LMUT

DI–2148

–

DIAGNOSTICS

REAR SEAT ENTERTAINMANT SYSTEM

2342

INSPECTION PROCEDURE

1

Inspect multi–display controller sub–assy.

PREPARATION:
Make sure that the R23 connector is connected.
CHECK:
Measure the voltage according to the value(s) in the table be-
low.
OK:

Symbol (Tester connection)

Condition

Specification

RMUT (R23–28) –

Body ground

Turn ignition switch to

ACC, Audio system is
sounding 

→

Changing

Above 3.5 V 

→

 Below 1 V

LMUT (R23–12) –

Body ground

Turn ignition switch to

ACC, RSE system is

sounding 

→

Changing

Above 3.5 V 

→

 Below 1 V

OK

Proceed to next circuit inspection shown in
problem symptoms table (See page 

DI–2087

).

NG

2

Check system.

CHECK:
Check whether the vehicle is equipped with a navigation system or not.
RESULT:

w/o Navigation system

Go to step A

w/ Navigation system

Go to step B

B

Go to step 5.

A

I28619

Radio Receiver Assy 
Wire Harness View:

MUTE

R20

I28605

RMU

R19

Radio Receiver Assy 
Wire Harness View:

I29009

Multi–display Controller Sub–assy:

RMUT

R23

LMUT

–

DIAGNOSTICS

REAR SEAT ENTERTAINMANT SYSTEM

DI–2149

2343

3

Check harness and connector (Radio receiver assy – Multi–display controller
sub–assy).

PREPARATION:
Disconnect the R19, R20 and R23 connectors.
CHECK:
Measure the resistance according to the value(s) in the table
below.
OK:

Symbol (Tester connection)

Condition

Specified condition

RMUT (R23–28) – RMU (R19–19)

Always

Below 1 

Ω

LMUT (R23–12) – MUTE (R20–6)

Always

Below 1 

Ω

RMUT (R23–28) – Body ground

Always

10 k

Ω 

or higher

LMUT (R23–12) – Body ground1

Always

10 k

Ω 

or higher

NG

Repair or replace harness or connector.

OK

DI–2150

–

DIAGNOSTICS

REAR SEAT ENTERTAINMANT SYSTEM

2344

4

Replace multi–display controller sub–assy.

CHECK:
Replace the multi–display controller sub–assy and check if it operates normally.
OK:

Normal operation.

OK

Normal operation.

NG

Replace radio receiver assy.