Toyota Avalon (XX50) 2019-2022 Service & Repair Manual: Telephone Microphone Error (B1572)

Toyota Avalon (XX50) 2019-2022 Service & Repair Manual / Audio, Visual, Telematics / Cellular Communication / Safety Connect System(for Gasoline Model) / Telephone Microphone Error (B1572)

DESCRIPTION

This DTC is set when the DCM (Telematics Transceiver) detects a malfunction in the telephone microphone assembly circuit.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

B1572

Telephone Microphone Error

Current of MCVD reaches malfunction criteria for 10 seconds while engine switch is on (IG).
  • Wire harness or connector
  • Telephone microphone assembly
  • Roof console box sub-assembly
  • DCM (Telematics Transceiver)

WIRING DIAGRAM

w/o Sliding Roof w/ Sliding Roof

CAUTION / NOTICE / HINT

HINT:

Before performing this diagnostic procedure, make sure to perform Health Check and confirm that the DCM/VIN registration information is correct.

Click here

PROCEDURE

1.

CONFIRM MODEL

(a) Choose the model to be inspected.

Result

Proceed to

w/ Sliding Roof

A

w/o Sliding Roof

B
B

GO TO STEP 8

A

2.

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.

(d) Turn the Techstream on.

(e) Clear the DTCs.

Body Electrical > Telematics > Clear DTCs

(f) Recheck for DTCs.

Body Electrical > Telematics > Trouble Codes

Result

Proceed to

DTC B1572 is output

A

DTC B1572 is not output

B
B

CHECK FOR INTERMITTENT PROBLEMS

A

3.

INSPECT ROOF CONSOLE BOX SUB-ASSEMBLY (TELEPHONE MICROPHONE ASSEMBLY POWER SOURCE)

(a) Remove the roof console box sub-assembly but do not disconnect the connectors.

Click here

*a

Component with harness connected

(Roof Console Box Sub-assembly)

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

O10-9 (MACC) - Body ground

Engine switch on (ACC)

4 to 6 V

Standard Resistance:

Tester Connection

Condition

Specified Condition

O10-7 (MCO-) - Body ground

Always

Below 1 Ω
NG

GO TO STEP 6

OK

4.

CHECK HARNESS AND CONNECTOR (DCM (TELEMATICS TRANSCEIVER) - ROOF CONSOLE BOX ASSEMBLY)

(a) Disconnect the G9 DCM (Telematics Transceiver) connector.

(b) Disconnect the O10 roof console box sub-assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

G9-34 (MCI+) - O10-8 (MCO+)

Always

Below 1 Ω

G9-34 (MCI+) or O10-8 (MCO+) - Body ground

Always

10 kΩ or higher

G9-35 (MCI-) - O10-7 (MCO-)

Always

Below 1 Ω

G9-35 (MCI-) or O10-7 (MCO-) - Body ground

Always

10 kΩ or higher

G9-32 (SGND) - Body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

5.

REPLACE TELEPHONE MICROPHONE ASSEMBLY

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

Click here

OK:

The system returns to normal.

OK

END
NG

REPLACE ROOF CONSOLE BOX SUB-ASSEMBLY

6.

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

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

Click here

*a

Component with harness connected

(DCM (Telematics Transceiver))

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

G9-33 (MCVD) - Body ground

Engine switch on (ACC)

4 to 6 V

Standard Resistance:

Tester Connection

Condition

Specified Condition

G9-35 (MCI-) - Body ground

Always

Below 1 Ω
OK

REPAIR OR REPLACE HARNESS OR CONNECTOR
NG

7.

REPLACE DCM (TELEMATICS TRANSCEIVER)

(a) Replace the DCM (Telematics Transceiver).

Click here

NOTICE:

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

PERFORM DCM ACTIVATION

8.

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.

(d) Turn the Techstream on.

(e) Clear the DTCs.

Body Electrical > Telematics > Clear DTCs

(f) Recheck for DTCs.

Body Electrical > Telematics > Trouble Codes

Result

Proceed to

DTC B1572 is output

A

DTC B1572 is not output

B
B

CHECK FOR INTERMITTENT PROBLEMS

A

9.

INSPECT ROOF CONSOLE BOX SUB-ASSEMBLY (TELEPHONE MICROPHONE ASSEMBLY POWER SOURCE)

(a) Remove the roof console box sub-assembly but do not disconnect the connectors.

Click here

*a

Component with harness connected

(Roof Console Box Sub-assembly)

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

O9-6 (MACC) - Body ground

Engine switch on (ACC)

4 to 6 V

Standard Resistance:

Tester Connection

Condition

Specified Condition

O9-4 (MCO-) - Body ground

Always

Below 1 Ω
NG

GO TO STEP 12

OK

10.

CHECK HARNESS AND CONNECTOR (DCM (TELEMATICS TRANSCEIVER) - ROOF CONSOLE BOX ASSEMBLY)

(a) Disconnect the G9 DCM (Telematics Transceiver) connector.

(b) Disconnect the O9 roof console box sub-assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

G9-34 (MCI+) - O9-5 (MCO+)

Always

Below 1 Ω

G9-34 (MCI+) or O9-5 (MCO+) - Body ground

Always

10 kΩ or higher

G9-35 (MCI-) - O9-4 (MCO-)

Always

Below 1 Ω

G9-35 (MCI-) or O9-4 (MCO-) - Body ground

Always

10 kΩ or higher

G9-32 (SGND) - Body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

11.

REPLACE TELEPHONE MICROPHONE ASSEMBLY

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

Click here

OK:

The system returns to normal.

OK

END
NG

REPLACE ROOF CONSOLE BOX SUB-ASSEMBLY

12.

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

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

Click here

*a

Component with harness connected

(DCM (Telematics Transceiver))

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

G9-33 (MCVD) - Body ground

Engine switch on (ACC)

4 to 6 V

Standard Resistance:

Tester Connection

Condition

Specified Condition

G9-35 (MCI-) - Body ground

Always

Below 1 Ω
OK

REPAIR OR REPLACE HARNESS OR CONNECTOR
NG

13.

REPLACE DCM (TELEMATICS TRANSCEIVER)

(a) Replace the DCM (Telematics Transceiver).

Click here

NOTICE:

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

PERFORM DCM ACTIVATION

    Manual (SOS) Switch Green Indicator Malfunction (B1571)

    Short in Telephone Antenna Circuit (B1573,B15CB)

    See More:

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