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

1. Turn the engine switch off.
2. Connect the Techstream to the DLC3.
3. Turn the engine 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 G128 DCM (telematics transceiver) connector.
2. Disconnect the P24 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
   G128-5 (MCVD) - P24-1 (MAC1)	Always	Below 1 Ω
   G128-6 (MCI+) - P24-2 (MO1+)	Always	Below 1 Ω
   G128-7 (MCI-) - P24-4 (MO1-)	Always	Below 1 Ω
   G128-23 (SGND) - Body ground	Always	10 kΩ or higher
   G128-5 (MCVD) or P24-1 (MAC1) - Body ground	Always	10 kΩ or higher
   G128-6 (MCI+) or P24-2 (MO1+) - Body ground	Always	10 kΩ or higher
   G128-7 (MCI-) or P24-4 (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 - ]

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
   P24-1 (MAC1) - Body ground	Engine switch on (IG)	7.5 to 8.5 V

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   P24-4 (MO1-) - Body ground	Always	Below 1 Ω

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE TELEPHONE MICROPHONE ASSEMBLY LH. Refer to  REMOVAL [09/2022 - ] 

Result: 

NG 

See step  4

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

   Refer to REMOVAL [09/2022 - ]

   NOTE:

   • The engine 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 [10/2019 - ]