DTC B1572-13: Microphone Circuit Open [09/2022 - ]: Procedure

1. Turn the power switch off.
2. Connect the Techstream to the DLC3.
3. Turn the power switch on (IG) and wait for 10 seconds or more.
4. Turn the Techstream on.
5. Clear the DTCs.

   Body Electrical > Telematics > Clear DTCs 

6. Check for DTCs and check that no DTCs are output.

   Body Electrical > Telematics > Trouble Codes 

   OK

   No DTCs are output.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

USE SIMULATION METHOD TO CHECK 

Refer to HOW TO PROCEED WITH TROUBLESHOOTING [06/2018 - ]

Result: 

NG 

See step  2

1. Disconnect the I143 telematics transceiver connector.
2. Disconnect the T24 telephone microphone assembly LH connector.
3. Measure the resistance according to the value(s) in the table below.

   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
   I143-23 (SGND) - Body ground	Always	10 kΩ or higher
   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

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  3

1. Remove the telephone microphone assembly LH but do not disconnect the connectors.

   Refer to REMOVAL [09/2022 - 11/2022] , or refer to REMOVAL [11/2022 - ]

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

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Component with harness connected (Telephone Microphone Assembly LH)

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   T24-1 (MAC1) - Body ground	Power switch on (IG)	7.5 to 8.5 V

   Standard Resistance

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

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE TELEPHONE MICROPHONE ASSEMBLY LH 

Refer to REMOVAL [09/2022 - 11/2022] , or refer to REMOVAL [11/2022 - ]

Result: 

NG 

See step  4

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

   Refer to REMOVAL [09/2022 - 11/2022] , or refer to REMOVAL [11/2022 - 09/2024] , or refer to REMOVAL [09/2024 - ]

   NOTE:

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

   Result

   Proceed to
   NEXT

Result: 

NEXT 

PERFORM DCM ACTIVATION 

Refer to DCM ACTIVATION [04/2020 - ]