AUDIO / VIDEO: AUDIO AND VISUAL SYSTEM (for Gasoline Model with Dual Knob Type): Mute Signal Circuit between Radio Receiver and Stereo Component Amplifier; 2020 - 2023 MY Corolla Corolla Hatchback GR Corolla [01/2019

Last Modified: 07-31-2024	6.11:8.1.0	Doc ID: RM100000001GL4P
Model Year Start: 2020	Model: GR Corolla	Prod Date Range: [01/2019 - 11/2022]
Title: AUDIO / VIDEO: AUDIO AND VISUAL SYSTEM (for Gasoline Model with Dual Knob Type): Mute Signal Circuit between Radio Receiver and Stereo Component Amplifier; 2020 - 2023 MY Corolla Corolla Hatchback GR Corolla [01/2019 - 11/2022]

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

CAUTION / NOTICE / HINT

NOTICE:

Depending on the parts that are replaced during vehicle inspection or maintenance, performing initialization, registration or calibration may be needed. Refer to Precaution for Audio and Visual System.
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When replacing the radio and display receiver assembly, always replace it with a new one. If a radio and display receiver assembly which was installed to another vehicle is used, the following may occur:
- A communication malfunction DTC may be stored.
- The radio and display receiver assembly may not operate normally.

PROCEDURE

1.	INSPECT STEREO COMPONENT AMPLIFIER ASSEMBLY

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

I68-1 (MUTE) - Body ground

Ignition switch ACC, audio system playing

→ Changing modes

2.0 V or higher

→ Below 1 V

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

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

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

(a) Disconnect the I55 radio and display receiver assembly connector.

(b) Disconnect the I68 stereo component amplifier assembly connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
I55-25 (MUT1) - I68-1 (MUTE)	Always	Below 1 Ω
I55-25 (MUT1) or I68-1 (MUTE) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

3.	INSPECT STEREO COMPONENT AMPLIFIER ASSEMBLY (OUTPUT SIGNAL)

(a) Reconnect the I68 stereo component amplifier assembly connector.

(b) Disconnect the I55 radio and display receiver assembly connector.

Standard Voltage:

Tester Connection	Condition	Specified Condition
I55-25 (MUT1) - Body ground	Ignition switch ACC, audio system is playing	2.0 V or higher

*a	Front view of wire harness connector (to Radio and Display Receiver Assembly)

REPLACE RADIO AND DISPLAY RECEIVER ASSEMBLY

REPLACE STEREO COMPONENT AMPLIFIER ASSEMBLY