AUDIO AND VISUAL SYSTEM(for Radio Receiver Type) Microphone Circuit between Microphone and Radio Receiver

DESCRIPTION

• The radio receiver assembly and map light assembly (telephone microphone assembly) are connected to each other using the microphone connection detection signal lines.

• Using this circuit, the radio receiver assembly sends power to the map light assembly (telephone microphone assembly), and the map light assembly (telephone microphone assembly) sends microphone signals to the radio receiver assembly.

WIRING DIAGRAM

*a	Telephone Microphone Assembly
*b	Shielded
*c	Map Light Assembly
*d	Radio Receiver Assembly

PROCEDURE

1. CHECK HARNESS AND CONNECTOR (RADIO RECEIVER ASSEMBLY - MAP LIGHT ASSEMBLY)

   
   

   1. Disconnect the G171 radio receiver assembly connector.

   2. Disconnect the Q2 map light assembly (telephone microphone assembly) connector.

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

      Standard Resistance

      Tester Connection Condition Specified Condition G171-4 (MACC) - Q2-15 (MACC) Always Below 1 Ω G171-5 (MIN+) - Q2-14 (MCO+) Always Below 1 Ω G171-19 (MIN-) - Q2-13 (MCO-) Always Below 1 Ω G171-18 (SGND) - Body ground Always 10 kΩ or higher G171-4 (MACC) or Q2-15 (MACC) - Body ground Always 10 kΩ or higher G171-5 (MIN+) or Q2-14 (MCO+) - Body ground Always 10 kΩ or higher G171-19 (MIN-) or Q2-13 (MCO-) - Body ground Always 10 kΩ or higher

      Result
      Proceed to OK NG

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

2. CHECK RADIO RECEIVER ASSEMBLY

   
   
   1. 

      *a	Component with harness connected (Radio Receiver Assembly)

      Remove the radio receiver assembly with its connectors still connected.

      Click here

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

      Standard Resistance
      Tester Connection Condition Specified Condition G171-19 (MIN-) - Body ground Always Below 1 Ω

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition G171-4 (MACC) - Body ground Ignition switch ACC 4 to 6 V

      Result
      Proceed to OK NG

   
   

   NG

   REPLACE RADIO RECEIVER ASSEMBLY Click here

   OK

3. CHECK MAP LIGHT ASSEMBLY

   
   
   1. 

      *a	Component with harness connected (Map Light Assembly)

      Remove the map light assembly with its connectors still connected.

      Click here

   2. Turn the ignition switch to ON.

   3. Connect an oscilloscope to terminals Q2-14 (MCO+) and Q2-13 (MCO-) of the map light assembly connector.

   4. Check the waveform of the telephone microphone assembly using the oscilloscope.

      Result
      Result Proceed to A waveform synchronized with the voice input to the map light assembly is output. A A waveform synchronized with the voice input to the map light assembly is not output. B

   
   

   B

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

   A

4. CHECK TELEPHONE MICROPHONE ASSEMBLY

   
   

   1. Replace the telephone microphone assembly.

      Click here

   2. Check if the same malfunction recurs.

      OK
      Malfunction does not recur (returns to normal).

      Result
      Proceed to OK NG

   
   

   OK

   END (TELEPHONE MICROPHONE ASSEMBLY IS DEFECTIVE)

   NG

   REPLACE MAP LIGHT ASSEMBLY Click here