NAVIGATION / MULTI INFO DISPLAY: NAVIGATION SYSTEM: Mute Signal Circuit between Radio Receiver and Telematics Transceiver; 2021 - 2023 MY Corolla Corolla Hatchback Corolla HV GR Corolla [04/2020

Last Modified: 07-31-2024	6.11:8.1.0	Doc ID: RM100000001NZGI
Model Year Start: 2021	Model: GR Corolla	Prod Date Range: [04/2020 - 11/2022]
Title: NAVIGATION / MULTI INFO DISPLAY: NAVIGATION SYSTEM: Mute Signal Circuit between Radio Receiver and Telematics Transceiver; 2021 - 2023 MY Corolla Corolla Hatchback Corolla HV GR Corolla [04/2020 - 11/2022]

Mute Signal Circuit between Radio Receiver and Telematics Transceiver

DESCRIPTION

The DCM (telematics transceiver) sends a mute signal to the radio and display receiver assembly.

The radio and display receiver assembly controls the volume according to the mute signal from the DCM (telematics transceiver).

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 Navigation 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.
Before replacing the DCM (telematics transceiver), refer to Registration.
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1.	INSPECT DCM (TELEMATICS TRANSCEIVER)

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

I143-14 (MUTE) - Body ground

Ignition switch ACC

Audio system playing

→ Emergency call mode

2.0 V or higher

→ Below 1 V

*a	Component with harness connected (DCM (Telematics Transceiver))

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

2.	CHECK HARNESS AND CONNECTOR (RADIO AND DISPLAY RECEIVER ASSEMBLY - DCM (TELEMATICS TRANSCEIVER))

(a) Disconnect the I56 radio and display receiver assembly connector.

(b) Disconnect the I143 DCM (telematics transceiver) connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
I56-3 (TMUT) - I143-14 (MUTE)	Always	Below 1 Ω
I56-3 (TMUT) or I143-14 (MUTE) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

3.	INSPECT RADIO AND DISPLAY RECEIVER ASSEMBLY

(a) Disconnect the I143 DCM (telematics transceiver) connector.

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
I143-14 (MUTE) - Body ground	Ignition switch ACC	2.0 V or higher

*a	Front view of wire harness connector (to DCM (Telematics Transceiver))

REPLACE DCM (TELEMATICS TRANSCEIVER)

REPLACE RADIO AND DISPLAY RECEIVER ASSEMBLY