Last Modified: 05-13-2024 6.11:8.1.0 Doc ID: RM100000001KLFE
Model Year Start: 2020 Model: GR Corolla Prod Date Range: [09/2019 - 04/2020]
Title: AUDIO / VIDEO: AUDIO AND VISUAL SYSTEM (for Gasoline Model with Dual Knob Type): B1579; Voice Recognition Microphone Disconnected; 2020 MY Corolla Corolla Hatchback GR Corolla [09/2019 - 04/2020]

DTC

B1579

Voice Recognition Microphone Disconnected

DESCRIPTION

The radio and display receiver assembly, map light assembly and telephone microphone assembly are connected to each other using the microphone connection detection signal lines.

This DTC is stored when a microphone connection detection signal line is disconnected.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

B1579

Voice Recognition Microphone Disconnected

Microphone signal is lost
  • Map light assembly
  • Telephone microphone assembly
  • Radio and display receiver assembly
  • DCM (telematics transceiver)*
  • Harness or connector
  • *: w/ Manual (SOS) Switch

WIRING DIAGRAM

for Hatchback Model
for Sedan Model

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.

    Click here 2020 - 2022 MY Corolla Corolla Hatchback GR Corolla [01/2019 - 09/2022]; AUDIO / VIDEO: AUDIO AND VISUAL SYSTEM (for Gasoline Model with Dual Knob Type): PRECAUTION

  • 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.

    Click here 2020 MY Corolla Corolla Hatchback GR Corolla [09/2019 - 04/2020]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, Gasoline Model): REGISTRATION

PROCEDURE

1.

INSPECT RADIO AND DISPLAY RECEIVER ASSEMBLY

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

I56-22 (MIN-) - Body ground

Always

Below 1 Ω

Result:

Result

Proceed to

OK (w/o Manual (SOS) Switch)

A

OK (for Hatchback Model with Manual (SOS) Switch)

B

OK (for Sedan Model with Manual (SOS) Switch)

C

NG

D

*a

Component with harness connected

(Radio and Display Receiver Assembly)
B

GO TO STEP 3

C

GO TO STEP 9

D

REPLACE RADIO AND DISPLAY RECEIVER ASSEMBLY

A

2.

CHECK HARNESS AND CONNECTOR (RADIO AND DISPLAY RECEIVER ASSEMBLY - MAP LIGHT ASSEMBLY)

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

(b) Disconnect the T6 map light assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

I56-25 (SNS2) - T6-4 (SNS2)

Always

Below 1 Ω

I56-22 (MIN-) - T6-5 (MCO-)

Always

Below 1 Ω

I56-25 (SNS2) or T6-4 (SNS2) - Body ground

Always

10 kΩ or higher

I56-22 (MIN-) or T6-5 (MCO-) - Body ground

Always

10 kΩ or higher
OK

GO TO STEP 13

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

3.

CHECK HARNESS AND CONNECTOR (DCM (TELEMATICS TRANSCEIVER) - MAP LIGHT ASSEMBLY)

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

(b) Disconnect the T6 map light assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

I143-7 (MCI-) - T6-5 (MCO-)

Always

Below 1 Ω

I143-7 (MCI-) or T6-5 (MCO-) - Body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

4.

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.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

I56-22 (MIN-) - I143-32 (MCO-)

Always

Below 1 Ω

I56-22 (MIN-) or I143-32 (MCO-) - Body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

5.

CHECK HARNESS AND CONNECTOR (RADIO AND DISPLAY RECEIVER ASSEMBLY - MAP LIGHT ASSEMBLY)

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

(b) Disconnect the T6 map light assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

I56-25 (SNS2) - T6-4 (SNS2)

Always

Below 1 Ω

I56-25 (SNS2) or T6-4 (SNS2) - Body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

6.

INSPECT DCM (TELEMATICS TRANSCEIVER)

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

(b) Connect the I56 radio and display receiver assembly connector.

(c) 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

*a

Component with harness connected

(DCM (Telematics Transceiver))
NG

REPLACE DCM (TELEMATICS TRANSCEIVER)

OK

7.

INSPECT MAP LIGHT ASSEMBLY

(a) Remove the map light assembly.

Click here 2020 - 2022 MY Corolla Corolla Hatchback Corolla HV GR Corolla [01/2019 - 09/2022]; LIGHTING (INT): PERSONAL LIGHT: REMOVAL

(b) Connect the B telephone microphone assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

4 (SNS2) - 5 (MCO-)

Always

Below 1 Ω

*a

Component without harness connected

(Map Light Assembly)
OK

REPLACE RADIO AND DISPLAY RECEIVER ASSEMBLY

NG

8.

INSPECT MAP LIGHT ASSEMBLY

(a) Remove the map light assembly.

Click here 2020 - 2022 MY Corolla Corolla Hatchback Corolla HV GR Corolla [01/2019 - 09/2022]; LIGHTING (INT): PERSONAL LIGHT: REMOVAL

(b) Disconnect the B telephone microphone assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

B-1 - T6-4 (SNS2)

Always

Below 1 Ω

B-2 - T6-5 (MCO-)

Always

Below 1 Ω

B-1 or T6-4 (SNS2) - T6-11 (GND)

Always

10 kΩ or higher

B-2 or T6-5 (MCO-) - T6-11 (GND)

Always

10 kΩ or higher

*a

Component without harness connected

(Map Light Assembly (No. 1 Roof Wire Side))

*b

Component without harness connected

(Map Light Assembly (Telephone Microphone Assembly Side))
OK

REPLACE TELEPHONE MICROPHONE ASSEMBLY

NG

REPLACE MAP LIGHT ASSEMBLY

9.

CHECK HARNESS AND CONNECTOR (DCM (TELEMATICS TRANSCEIVER) - MAP LIGHT ASSEMBLY)

(a) Disconnect the I72 DCM (telematics transceiver) connector.

(b) Disconnect the T6 map light assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

I72-35 (MCI-) - T6-5 (MCO-)

Always

Below 1 Ω

I72-35 (MCI-) or T6-5 (MCO-) - Body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

10.

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 I72 DCM (telematics transceiver) connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

I56-22 (MIN-) - I72-19 (MCO-)

Always

Below 1 Ω

I56-22 (MIN-) or I72-19 (MCO-) - Body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

11.

CHECK HARNESS AND CONNECTOR (RADIO AND DISPLAY RECEIVER ASSEMBLY - MAP LIGHT ASSEMBLY)

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

(b) Disconnect the T6 map light assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

I56-25 (SNS2) - T6-4 (SNS2)

Always

Below 1 Ω

I56-25 (SNS2) or T6-4 (SNS2) - Body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

12.

INSPECT DCM (TELEMATICS TRANSCEIVER)

(a) Connect the I72 DCM (telematics transceiver) connector.

(b) Connect the I56 radio and display receiver assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

I72-35 (MCI-) - Body ground

Always

Below 1 Ω

*a

Component with harness connected

(DCM (Telematics Transceiver))
NG

REPLACE DCM (TELEMATICS TRANSCEIVER)

OK

13.

INSPECT MAP LIGHT ASSEMBLY

(a) Remove the map light assembly.

Click here 2020 - 2022 MY Corolla Corolla Hatchback Corolla HV GR Corolla [01/2019 - 09/2022]; LIGHTING (INT): PERSONAL LIGHT: REMOVAL

(b) Connect the B telephone microphone assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

4 (SNS2) - 5 (MCO-)

Always

Below 1 Ω

*a

Component without harness connected

(Map Light Assembly)
OK

REPLACE RADIO AND DISPLAY RECEIVER ASSEMBLY

NG

14.

INSPECT MAP LIGHT ASSEMBLY

(a) Remove the map light assembly.

Click here 2020 - 2022 MY Corolla Corolla Hatchback Corolla HV GR Corolla [01/2019 - 09/2022]; LIGHTING (INT): PERSONAL LIGHT: REMOVAL

(b) Disconnect the B telephone microphone assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

B-1 - T6-4 (SNS2)

Always

Below 1 Ω

B-2 - T6-5 (MCO-)

Always

Below 1 Ω

B-1 or T6-4 (SNS2) - T6-11 (GND)

Always

10 kΩ or higher

B-2 or T6-5 (MCO-) - T6-11 (GND)

Always

10 kΩ or higher

*a

Component without harness connected

(Map Light Assembly (No. 1 Roof Wire Side))

*b

Component without harness connected

(Map Light Assembly (Telephone Microphone Assembly Side))
OK

REPLACE TELEPHONE MICROPHONE ASSEMBLY

NG

REPLACE MAP LIGHT ASSEMBLY