Toyota Tacoma (2015-2018) Service Manual: Mute Signal Circuit between Radio Receiver and Stereo Component Amplifier

Toyota Tacoma (2015-2018) Service Manual / Navigation / Multi Info Display / Navigation System / Mute Signal Circuit between Radio Receiver and Stereo Component Amplifier

DESCRIPTION

This circuit sends a signal to the stereo component amplifier assembly to mute noise. Because of that, the noise produced 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 assembly is functioning normally, no sound or only an extremely faint sound can be heard.

WIRING DIAGRAM

PROCEDURE

1.	INSPECT STEREO COMPONENT AMPLIFIER ASSEMBLY

(a) Remove the stereo component amplifier assembly with connectors still connected.

(b) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

S23-1 (MUTE) - Body ground

Ignition switch ACC, audio system playing

→ Changing modes

Above 3.5 V

→ Below 1 V

Text in Illustration

*a	Component with harness connected (Stereo Component Amplifier Assembly)

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

2.	CHECK HARNESS AND CONNECTOR (NAVIGATION RECEIVER ASSEMBLY - STEREO COMPONENT AMPLIFIER ASSEMBLY)

(a) Disconnect the N25 navigation receiver assembly connector.

(b) Disconnect the S23 stereo component amplifier assembly connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
N25-16 (MUT1) - S23-1 (MUTE)	Always	Below 1 Ω
N25-16 (MUT1) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

3.	INSPECT STEREO COMPONENT AMPLIFIER ASSEMBLY (OUTPUT SIGNAL)

(a) Reconnect the S23 stereo component amplifier assembly connector.

(b) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
N25-16 (MUT1) - Body ground	Ignition switch ACC, audio system is playing	Above 3.5 V

Text in Illustration

*a	Front view of wire harness connector (to Navigation Receiver Assembly)

REPLACE NAVIGATION RECEIVER ASSEMBLY

REPLACE STEREO COMPONENT AMPLIFIER ASSEMBLY

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