AUDIO / VIDEO: AUDIO AND VISUAL SYSTEM (for Single Knob Type): Microphone Circuit; 2023 - 2025 MY Corolla Corolla Hatchback Corolla HV GR Corolla [09/2022

Last Modified: 05-13-2024	6.11:8.1.0	Doc ID: RM10000000272EE
Model Year Start: 2023	Model: GR Corolla	Prod Date Range: [09/2022 - ]
Title: AUDIO / VIDEO: AUDIO AND VISUAL SYSTEM (for Single Knob Type): Microphone Circuit; 2023 - 2025 MY Corolla Corolla Hatchback Corolla HV GR Corolla [09/2022 - ]

Microphone Circuit

WIRING DIAGRAM

w/ DCM (Telematics Transceiver)

w/o DCM (Telematics Transceiver)

CAUTION / NOTICE / HINT

NOTICE:

When replacing the telematics transceiver, make sure to replace it with a new one (w/ Telematics Transceiver for LEXUS Connected Services or LEXUS Connect).
Depending on the parts that are replaced during vehicle inspection or maintenance, performing initialization, registration or calibration may be needed.
Click here

PROCEDURE

1.	CHECK MODEL

Result	Proceed to
w/ Telematics Transceiver	A
w/o Telematics Transceiver	B

GO TO STEP 15

2.	CHECK MICROPHONE

(a) Enter diagnostic mode.

Click here

*a	Mic 1 Input Level
*b	Mic 2 Input Level

(b) Select "Function Check/Setting" from the "Service Menu" screen.

(d) Speak into each microphone assembly and check the microphone input level gauge display.

OK:

The microphone input levels of the gauge change in accordance with the voice.

Result	Proceed to
Microphone input levels change for microphone 1 and 2	A
Microphone input level does not change for microphone 1	B
Microphone input level does not change for microphone 2	C

REPLACE RADIO AND DISPLAY RECEIVER ASSEMBLY

GO TO STEP 6

3.	CHECK HARNESS AND CONNECTOR (RADIO AND DISPLAY RECEIVER ASSEMBLY - TELEPHONE MICROPHONE ASSEMBLY RH)

(a) Disconnect the I176 radio and display receiver assembly connector.

(b) Disconnect the T25 telephone microphone assembly LH connector

Standard Resistance:

Tester Connection	Condition	Specified Condition
I176-17 (MI2+) - T25-2 (MO2+)	Always	Below 1 Ω
I176-18 (MI2-) - T25-4 (MO2-)	Always	Below 1 Ω
I176-20 (MAC2) - T25-1 (MAC2)	Always	Below 1 Ω
I176-21 (SNS2) - T25-5 (SNS2)	Always	Below 1 Ω
I176-17 (MI2+) or T25-2 (MO2+) - Body ground	Always	10 kΩ or higher
I176-18 (MI2-) or T25-4 (MO2-) - Body ground	Always	10 kΩ or higher
I176-20 (MAC2) or T25-1 (MAC2) - Body ground	Always	10 kΩ or higher
I176-21 (SNS2) or T25-5 (SNS2) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

4.	CHECK RADIO AND DISPLAY RECEIVER ASSEMBLY (MAC2, MI2-)

(a) With the I176 radio and display receiver assembly connector connected, disconnect the T25 telephone microphone assembly RH connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
T25-4(MO2-) - Body ground	Always	Below 1 Ω

Standard Voltage:

Tester Connection	Condition	Specified Condition
T25-1(MAC2) - Body ground	IG ON	7.5 to 8.5 V

REPLACE RADIO AND DISPLAY RECEIVER ASSEMBLY

5.	CHECK TELEPHONE MICROPHONE ASSEMBLY LH (OUTPUT TO RADIO AND DISPLAY RECEIVER ASSEMBLY)

(a) Using an oscilloscope, measure the waveform according to the condition(s) in the table below.

Item	Condition
Tester Connection	T25-2 (MO2+) - T25-4 (MO2-)
Tool setting	50 mV/DIV., 500 ms/DIV.
Vehicle condition	Turn the ignition switch to ON Sound is input to the telephone microphone assembly when the user is closer than 125 mm from the microphone case LH sound holes.

OK:

The waveform is similar to that shown in the illustration.

HINT:

The oscilloscope waveform shown in the illustration is an example for reference only.
In order to ensure that a consistent sound level is input to the microphone, use a digital voice recorder, etc., to play back sound in the same location with respect to the microphone.

*a	Component with harness connected (Telephone microphone assembly LH)

Result	Proceed to
A waveform synchronized with voice signals is output	A
A waveform synchronized with voice signals is not output	B

REPLACE RADIO AND DISPLAY RECEIVER ASSEMBLY

REPLACE TELEPHONE MICROPHONE ASSEMBLY RH

6.	CHECK TELEMATICS TRANSCEIVER (MICROPHONE POWER SOURCE AND BODY GROUND)

HINT:

Measure the connector of the telematics transceiver while it is connected.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
I143-7(MCI-) - Body ground	Always	Below 1 Ω
I143-23(SGND) - Body ground	Always	Below 1 Ω

*a	Component with harness connected (Telematics transceiver)

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
I143-5(MCVD) - Body ground	IG ON	7.5 to 8.5 V

GO TO STEP 13

7.	CHECK TELEMATICS TRANSCEIVER (OUTPUT TO RADIO AND DISPLAY RECEIVER ASSEMBLY)

HINT:

Measure the connector of the telematics transceiver while it is connected.

(a) Using an oscilloscope, measure the waveform according to the condition(s) in the table below.

Item	Condition
Tester Connection	I143-16 (MCO+) - I143-32 (MCO-)
Tool setting	50 mV/DIV, 500 ms/DIV
Vehicle condition	Turn the ignition switch to ON Sound is input to the telephone microphone assembly when the user is closer than 125 mm from the microphone case RH sound holes.

OK:

The waveform is similar to that shown in the illustration.

HINT:

The oscilloscope waveform shown in the illustration is an example for reference only.
In order to ensure that a consistent sound level is input to the microphone, use a digital voice recorder, etc., to play back sound in the same location with respect to the microphone.

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

Result	Proceed to
A waveform synchronized with voice signals is output	A
A waveform synchronized with voice signals is not output	B

GO TO STEP 9

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

(a) Disconnect the I175 radio and display receiver assembly connector.

(b) Disconnect the I143 Telematics transceiver connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
I175-21 (MIN+) - I143-16 (MCO+)	Always	Below 1 Ω
I175-22 (MIN-) - I143-32 (MCO-)	Always	Below 1 Ω
I175-21 (MIN+) or I143-16 (MCO+) - Body ground	Always	10 kΩ or higher
I175-22 (MIN-) or I143-32 (MCO-) - Body ground	Always	10 kΩ or higher

REPLACE RADIO AND DISPLAY RECEIVER ASSEMBLY

REPAIR OR REPLACE HARNESS OR CONNECTOR

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

(a) Disconnect the I175 radio and display receiver assembly connector.

(b) Disconnect the I143 Telematics transceiver connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
I175-21 (MIN+) - I143-16(MCO+)	Always	Below 1 Ω
I175-22 (MIN-) - I143-32 (MCO-)	Always	Below 1 Ω
I175-21 (MIN+) or I143-16 (MCO+) - Body ground	Always	10 kΩ or higher
I175-22 (MIN-) or I143-32 (MCO-) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

10.	CHECK HARNESS AND CONNECTOR (TELEMATICS TRANSCEIVER - TELEPHONE MICROPHONE ASSEMBLY LH)

(a) Disconnect the I143 Telematics transceiver connector.

(b) Disconnect the T24 telephone microphone assembly LH connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
I143-5 (MCVD) - T24-1 (MAC1)	Always	Below 1 Ω
I143-6 (MCI+) - T24-2 (MO1+)	Always	Below 1 Ω
I143-7 (MCI-) - T24-4 (MO1-)	Always	Below 1 Ω
I143-5 (MCVD) or T24-1(MAC1) - Body ground	Always	10 kΩ or higher
I143-6(MCI+) or T24-2 (MO1+) - Body ground	Always	10 kΩ or higher
I143-7 (MCI-) or T24-4 (MO1-) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

11.	CHECK HARNESS AND CONNECTOR (RADIO AND DISPLAY RECEIVER ASSEMBLY - TELEPHONE MICROPHONE ASSEMBLY LH)

(a) Disconnect the I175 radio and display receiver assembly connector.

(b) Disconnect the T24 telephone microphone assembly LH connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
I175-25 (SNS) - T24-5 (SNS1)	Always	Below 1 Ω
I175-25 (SNS) or T24-5 (SNS1) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

12.	CHECK TELEPHONE MICROPHONE ASSEMBLY LH (OUTPUT TO TELEMATICS TRANSCEIVER)

(a) Using an oscilloscope, measure the waveform according to the condition(s) in the table below.

Item	Condition
Tester Connection	T24-2 (MO1+) - T24-4 (MO1-)
Tool setting	50 mV/DIV, 500 ms/DIV
Vehicle condition	Turn the ignition switch to ON Sound is input to the telephone microphone assembly when the user is closer than 125 mm from the microphone case RH sound holes.

OK:

The waveform is similar to that shown in the illustration.

HINT:

The oscilloscope waveform shown in the illustration is an example for reference only.
In order to ensure that a consistent sound level is input to the microphone, use a digital voice recorder, etc., to play back sound in the same location with respect to the microphone.

*a	Component with harness connected (DCM (Telephone microphone assembly RH))

Result	Proceed to
A waveform synchronized with voice signals is output	A
A waveform synchronized with voice signals is not output	B

REPLACE DCM (TELEMATICS TRANSCEIVER)

REPLACE TELEPHONE MICROPHONE ASSEMBLY LH

13.	CHECK HARNESS AND CONNECTOR (TELEMATICS TRANSCEIVER - TELEPHONE MICROPHONE ASSEMBLY LH)

(a) Disconnect the I143 Telematics transceiver connector.

(b) Disconnect the T24 telephone microphone assembly LH connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
I143-5 (MCVD) - T24-1 (MAC1)	Always	Below 1 Ω
I143-6 (MCI+) - T24-2 (MO1+)	Always	Below 1 Ω
I143-7 (MCI-) - T24-4 (MO1-)	Always	Below 1 Ω
I143-5 (MCVD) or T24-1 (MAC1) - Body ground	Always	10 kΩ or higher
I143-6 (MCI+) or T24-2 (MO1+) - Body ground	Always	10 kΩ or higher
I143-7 (MCI-) or T24-4 (MO1-) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

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

(a) Disconnect the I175 radio and display receiver assembly connector.

(b) Disconnect the I143 telematics transceiver connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
I175-21 (MIN+) - I143-16 (MCO+)	Always	Below 1 Ω
I175-22 (MIN-) - I143-32 (MCO-)	Always	Below 1 Ω
I175-21 (MIN+) or I143-16 (MCO+) - Body ground	Always	10 kΩ or higher
I175-22 (MIN-) or I143-32 (MCO-) - Body ground	Always	10 kΩ or higher

REPLACE DCM (TELEMATICS TRANSCEIVER)

REPAIR OR REPLACE HARNESS OR CONNECTOR

15.	CHECK MICROPHONE

(a) Enter diagnostic mode.

Click here

*a	Mic 1 Input Level
*b	Mic 2 Input Level

(b) Select "Function Check/Setting" from the "Service Menu" screen.

(d) Speak into each microphone assembly and check the microphone input level gauge display.

OK:

The microphone input levels of the gauge change in accordance with the voice.

Result	Proceed to
Microphone input levels change for microphone 1 and 2	A
Microphone input level does not change for microphone 1	B
Microphone input level does not change for microphone 2	C

REPLACE RADIO AND DISPLAY RECEIVER ASSEMBLY

GO TO STEP 19

16.	CHECK HARNESS AND CONNECTOR (RADIO AND DISPLAY RECEIVER ASSEMBLY - TELEPHONE MICROPHONE ASSEMBLY RH)

(a) Disconnect the I176 radio and display receiver assembly connector.

(b) Disconnect the T25 telephone microphone assembly RH connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
I176-17 (MI2+) - T25-2 (MO2+)	Always	Below 1 Ω
I176-18 (MI2-) - T25-4 (MO2-)	Always	Below 1 Ω
I176-20 (MAC2) - T25-1 (MAC2)	Always	Below 1 Ω
I176-21 (SNS2) - T25-5 (SNS2)	Always	Below 1 Ω
I176-17 (MI2+) or T25-2 (MO2+) - Body ground	Always	10 kΩ or higher
I176-18 (MI2-) or T25-4 (MO2-) - Body ground	Always	10 kΩ or higher
I176-20 (MAC2) or T25-1 (MAC2) - Body ground	Always	10 kΩ or higher
I176-21 (SNS2) or T25-5 (SNS2) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

17.	INSPECT RADIO AND DISPLAY RECEIVER ASSEMBLY (MO2, MI2-)

(a) With the I176 radio and display receiver assembly connector connected, disconnect the T25 telephone microphone assembly RH connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
T25-4 (MO2-) - Body ground	Always	Below 1 Ω

Standard Voltage:

Tester Connection	Condition	Specified Condition
T25-1 (MAC2) - Body ground	IG ON	7.5 to 8.5 V

REPLACE RADIO AND DISPLAY RECEIVER ASSEMBLY

18.	INSPECT TELEPHONE MICROPHONE ASSEMBLY RH (OUTPUT TO RADIO AND DISPLAY RECEIVER ASSEMBLY)

(a) Using an oscilloscope, measure the waveform according to the condition(s) in the table below.

Item	Condition
Tester Connection	T25-2(MO1+) - T25-4(MO1-)
Tool setting	50 mV/DIV., 500 ms/DIV.
Vehicle condition	Turn the ignition switch to ON Sound is input to the telephone microphone assembly when the user is closer than 125 mm from the microphone case LH sound holes.

OK:

The waveform is similar to that shown in the illustration.

HINT:

The oscilloscope waveform shown in the illustration is an example for reference only.
In order to ensure that a consistent sound level is input to the microphone, use a digital voice recorder, etc., to play back sound in the same location with respect to the microphone.

*a	Component with harness connected (DCM (Telephone microphone assembly LH))

Result	Proceed to
A waveform synchronized with voice signals is output	A
A waveform synchronized with voice signals is not output	B

REPLACE RADIO AND DISPLAY RECEIVER ASSEMBLY

REPLACE TELEPHONE MICROPHONE ASSEMBLY RH

19.	CHECK HARNESS AND CONNECTOR (RADIO AND DISPLAY RECEIVER ASSEMBLY - TELEPHONE MICROPHONE ASSEMBLY LH)

(a) Disconnect the I175 radio and display receiver assembly connector.

(b) Disconnect the T24 telephone microphone assembly RH connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
I175-17(MI2+) - T24-2(MO2+)	Always	Below 1 Ω
I175-18(MI2-) - T24-4(MO2-)	Always	Below 1 Ω
I175-20(MAC2) - T24-1(MAC2)	Always	Below 1 Ω
I175-21(SNS2) - T24-5(SNS2)	Always	Below 1 Ω
I175-17(MI2+) or T24-2(MO2+) - Body ground	Always	10 kΩ or higher
I175-18(MI2-) or T24-4(MO2-) - Body ground	Always	10 kΩ or higher
I175-20(MAC2) or T24-1(MAC2) - Body ground	Always	10 kΩ or higher
I175-21(SNS2) or T24-5(SNS2) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

20.	INSPECT RADIO AND DISPLAY RECEIVER ASSEMBLY (MACC, MIN-)

(a) With the I175 radio and display receiver assembly connector connected, disconnect the M11 telephone microphone assembly RH connecter.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
T24-4 (MO1-) - Body ground	Always	Below 1 Ω

Standard Voltage:

Tester Connection	Condition	Specified Condition
T24-1(MAC1) - Body ground	IG ON	7.5 to 8.5 V

REPLACE RADIO AND DISPLAY RECEIVER ASSEMBLY

21.	INSPECT TELEPHONE MICROPHONE ASSEMBLY LH (OUTPUT TO RADIO AND DISPLAY RECEIVER ASSEMBLY)

(a) Using an oscilloscope, measure the waveform according to the condition(s) in the table below.

Item	Condition
Tester Connection	T24-2(MO1+) - T24-4(MO1-)
Tool setting	50 mV/DIV., 500 ms/DIV.
Vehicle condition	Turn the ignition switch to ON Sound is input to the telephone microphone assembly when the user is closer than 125 mm from the microphone case RH sound holes.

OK:

The waveform is similar to that shown in the illustration.

HINT:

The oscilloscope waveform shown in the illustration is an example for reference only.
In order to ensure that a consistent sound level is input to the microphone, use a digital voice recorder, etc., to play back sound in the same location with respect to the microphone.

*a	Component with harness connected (Telephone microphone assembly RH)

Result	Proceed to
A waveform synchronized with voice signals is output	A
A waveform synchronized with voice signals is not output	B

REPLACE RADIO AND DISPLAY RECEIVER ASSEMBLY

REPLACE TELEPHONE MICROPHONE ASSEMBLY RH