Toyota 4Runner manuals

Toyota 4Runner: Telephone Microphone Error (B1572)

DESCRIPTION

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

DTC Code

DTC Detection Condition

Trouble Area

B1572

Current of MCVD reaches the malfunction criteria for 10 seconds when the ignition switch is ON.

  • Harness or connector
  • Telephone microphone assembly
  • Map light assembly
  • DCM (Telematics Transceiver)

WIRING DIAGRAM


PROCEDURE

1.

CHECK FOR DTC

(a) Turn the ignition switch off.

(b) Connect the Techstream to the DLC3.

(c) Turn the ignition switch to ON and wait for 10 seconds.

(d) Perform "Health Check" and check for current DTCs (See page ).


Result

Result

Proceed to

DTC B1572 is output

A

DTC B1572 is not output

B


B

CHECK FOR INTERMITTENT PROBLEMS

A

2.

CHECK MAP LIGHT ASSEMBLY (TELEPHONE MICROPHONE POWER SOURCE)

(a) Remove the map light assembly with the connector connected (See page ).



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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

U2-14 (MACC) - Body ground

Ignition switch ON

4 to 6 V

Text in Illustration

*a

Component with harness connected

(Map Light Assembly)


NG

GO TO STEP 5

OK

3.

CHECK HARNESS AND CONNECTOR (DCM - MAP LIGHT ASSEMBLY)

(a) Disconnect the F39 DCM (Telematics Transceiver) connector.


(b) Disconnect the U2 map light assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

F39-34 (MCI+) - U2-13 (MCO+)

Always

Below 1 Ω

F39-35 (MCI-) - U2-12 (MCO-)

Always

Below 1 Ω

F39-34 (MCI+) - Body ground

Always

10 kΩ or higher

F39-35 (MCI-) - Body ground

Always

10 kΩ or higher

F39-32 (SGND) - Body ground

Always

10 kΩ or higher

Text in Illustration

*a

Front view of wire harness connector

(to DCM [Telematics Transceiver])

*b

Front view of wire harness connector

(to Map Light Assembly)


NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

4.

REPLACE TELEPHONE MICROPHONE ASSEMBLY

(a) Replace the telephone microphone assembly with a normal one and check that the same problem does not occur again (See page
).

OK:

The system returns to normal.


OK

END


NG

REPLACE MAP LIGHT ASSEMBLY

5.

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

(a) Remove the DCM (Telematics Transceiver) with the connectors connected (See page ).



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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

F39-33 (MCVD) - Body ground

Ignition switch ON

4 to 6 V

Text in Illustration

*a

Component with harness connected

(DCM [Telematics Transceiver])


OK

REPAIR OR REPLACE HARNESS OR CONNECTOR

NG

6.

REPLACE DCM (TELEMATICS TRANSCEIVER)

(a) Replace the DCM (Telematics Transceiver) (See page ).


NOTICE:

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

NEXT

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