DTC B1572: Telephone Microphone Error [03/2017 - 06/2017]: 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.
4. Turn the Techstream on.
5. Clear the DTCs.

   Body Electrical > Telematics > Clear DTCs 

6. Recheck for DTCs.

   Body Electrical > Telematics > Trouble Codes 

   Result

   Result	Proceed to
   DTC B1572 is output	A
   DTC B1572 is not output	B

Result: 

B 

CHECK FOR INTERMITTENT PROBLEMS. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [03/2017 - 06/2017] 

Result: 

A 

See step  2

1. Remove the roof console box sub-assembly but do not disconnect the connectors.

   Refer to REMOVAL [03/2017 - ]

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Component with harness connected (Roof Console Box Sub-assembly)

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   V14-9 (MACC) - Body ground	Engine switch on (ACC)	4 to 6 V

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   V14-7 (MCO-) - Body ground	Always	Below 1 Ω

   Result

   Proceed to
   OK
   NG

Result: 

NG 

See step  5

Result: 

OK 

See step  3

1. Disconnect the K12 DCM (Telematics Transceiver) connector.
2. Disconnect the V14 roof console box sub-assembly connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   K12-34 (MCI+) - V14-8 (MCO+)	Always	Below 1 Ω
   K12-34 (MCI+) or V14-8 (MCO+) - Body ground	Always	10 kΩ or higher
   K12-35 (MCI-) - V14-7 (MCO-)	Always	Below 1 Ω
   K12-35 (MCI-) or V14-7 (MCO-) - Body ground	Always	10 kΩ or higher
   K12-32 (SGND) - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  4

1. Replace the telephone microphone assembly with a normal one and check if the same problem occurs again.

   Refer to REMOVAL [03/2017 - 06/2017]

   OK

   The system returns to normal.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

END 

Result: 

NG 

REPLACE ROOF CONSOLE BOX SUB-ASSEMBLY. Refer to  REMOVAL [03/2017 - ] 

1. Remove the DCM (Telematics Transceiver) but do not disconnect the connectors.

   Refer to REMOVAL [03/2017 - 09/2019]

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   K12-33 (MCVD) - Body ground	Engine switch on (ACC)	4 to 6 V

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   K12-35 (MCI-) - Body ground	Always	Below 1 Ω

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

NG 

See step  6

1. Replace the DCM (Telematics Transceiver).

   Refer to REMOVAL [03/2017 - 09/2019]

   NOTE:

   • The engine switch must be off.
   • Do not swap the DCM (Telematics Transceiver) with one from another vehicle.

   Result

   Proceed to
   NEXT

Result: 

NEXT 

PERFORM DCM ACTIVATION. Refer to  DCM ACTIVATION [03/2017 - 09/2019]