Last Modified: 05-13-2024 6.11:8.1.0 Doc ID: RM100000001LA4B
Model Year Start: 2020 Model: GR Corolla Prod Date Range: [09/2019 - 04/2020]
Title: CELLULAR COMMUNICATION: SAFETY CONNECT SYSTEM (for Hatchback, Gasoline Model): B157213; Microphone Circuit Open; 2020 MY Corolla Corolla Hatchback GR Corolla [09/2019 - 04/2020]

DTC

B157213

Microphone Circuit Open

DESCRIPTION

This DTC is stored when the DCM (telematics transceiver) detects a malfunction in the telephone microphone assembly circuit.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

B157213

Microphone Circuit Open

Current at terminal MCVD is lower than the malfunction threshold for 10 seconds or more while the engine switch is on (IG)
  • DCM (telematics transceiver)
  • Map light assembly
  • Telephone microphone assembly
  • Harness or connector

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 Safety Connect System.

Click here 2020 MY Corolla Corolla Hatchback GR Corolla [09/2019 - 04/2020]; CELLULAR COMMUNICATION: SAFETY CONNECT SYSTEM (for Hatchback, Gasoline Model): PRECAUTION

PROCEDURE

1.

CHECK DTC

(a) Turn the engine switch off.

(b) Connect the Techstream to the DLC3.

(c) Turn the engine switch on (IG) and wait for 10 seconds or more.

(d) Turn the Techstream on.

(e) Clear the DTCs.

Body Electrical > Telematics > Clear DTCs

(f) Check for DTCs and check that no DTCs are output.

Body Electrical > Telematics > Trouble Codes

OK:

No DTCs are output.

OK

USE SIMULATION METHOD TO CHECK

NG

2.

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

I72-5 (MCVD) - T6-7 (MACC)

Always

Below 1 Ω

I72-6 (MCI+) - T6-6 (MCO+)

Always

Below 1 Ω

I72-7 (MCI-) - T6-5 (MCO-)

Always

Below 1 Ω

I72-23 (SGND) - Body ground

Always

10 kΩ or higher

I72-5 (MCVD) or T6-7 (MACC) - Body ground

Always

10 kΩ or higher

I72-6 (MCI+) or T6-6 (MCO+) - Body ground

Always

10 kΩ or higher

I72-7 (MCI-) or T6-5 (MCO-) - Body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

3.

CHECK DCM (TELEMATICS TRANSCEIVER) (TELEPHONE MICROPHONE ASSEMBLY POWER SOURCE)

(a) Remove the map light assembly but do not disconnect the connectors.

Click here 2020 - 2022 MY Corolla Corolla Hatchback Corolla HV GR Corolla [01/2019 - 09/2022]; AUDIO / VIDEO: MICROPHONE: REMOVAL

*a

Component with harness connected

(Map Light Assembly)

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

T6-7 (MACC) - Body ground

Engine switch on (ACC)

4 to 6 V

Standard Resistance:

Tester Connection

Condition

Specified Condition

T6-5 (MCO-) - Body ground

Always

Below 1 Ω
OK

REPLACE TELEPHONE MICROPHONE ASSEMBLY

NG

4.

REPLACE DCM (TELEMATICS TRANSCEIVER)

(a) Replace the DCM (telematics transceiver) with a new one.

Click here 2020 MY Corolla Corolla Hatchback Corolla HV GR Corolla [09/2019 - 04/2020]; CELLULAR COMMUNICATION: DCM(TELEMATICS TRANSCEIVER): REMOVAL

NOTICE:

  • The engine switch must be off
  • Do not exchange the DCM (telematics transceiver) with one from another vehicle.
NEXT

PERFORM DCM ACTIVATION