NAVIGATION SYSTEM Mute Signal Circuit between Radio Receiver and Extension Module

DESCRIPTION

This circuit sends a signal to the navigation ECU to mute noise. Because of that, the noise produced by changing the sound source ceases.

If there is an open in the circuit, noise can be heard from the speakers when changing the sound source.

If there is a short in the circuit, even though the navigation ECU is functioning, no sound, or only an extremely faint sound, can be heard.

WIRING DIAGRAM

A01KTQ3E99
*a MUTE
*b Radio and Display Receiver Assembly
*c Navigation ECU

PROCEDURE


  1. INSPECT NAVIGATION ECU


    1. A01KRO5C05
      *a

      Component with harness connected

      (Navigation ECU)

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      V1-1 (MUTE) - Body ground

      Power switch on (ACC), audio system is playing

      → Changing modes

      3.5 V or higher

      → Below 1 V
      Result
      Proceed to
      OK
      NG

    OK

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here

    NG

  2. CHECK HARNESS AND CONNECTOR (RADIO AND DISPLAY RECEIVER ASSEMBLY - NAVIGATION ECU)


    1. Disconnect the V3 radio and display receiver assembly connector.

    2. Disconnect the V1 navigation ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      V3-6 (MUTE) - V1-1 (MUTE) Always Below 1 Ω
      V3-6 (MUTE) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. INSPECT RADIO AND DISPLAY RECEIVER ASSEMBLY (OUTPUT SIGNAL)


    1. Reconnect the V3 radio and display receiver assembly connector.

    2. A01KT85C04
      *a

      Front view of wire harness connector

      (to Navigation ECU)

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      V1-1 (MUTE) - Body ground Power switch on (ACC), audio system is playing 3.5 V or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE NAVIGATION ECU Click here

    NG

    REPLACE RADIO AND DISPLAY RECEIVER ASSEMBLY Click here