1.CHECK CONTINUITY BETWEEN AV CONTROL UNIT AND MICROPHONE CIRCUIT

1. Turn ignition switch OFF.
2. Disconnect AV control unit connector and microphone connector.
3. Check continuity between AV control unit harness connector and microphone harness connector.

   AV control unit | Microphone | Continuity
   Connector | Terminals | Connector | Terminals
   M203 | 71 | R5 | 2 | Existed
   72 | 4
   87 | 1

4. Check continuity between AV control unit harness connector and ground.

   AV control unit | Ground | Continuity
   Connector | Terminals
   M203 | 72 | Not existed
   87

Is the inspection result normal?
YES>>GO TO 2.
NO>>Repair harness or connector.
2.CHECK VOLTAGE MICROPHONE VCC

1. Connect AV control unit connector.
2. Turn ignition switch ON.
3. Check voltage between AV control unit harness connector.

   (+) | (−) | Voltage (Approx.)
   AV control unit | AV control unit
   Connector | Terminal | Connector | Terminal
   M203 | 72 | M203 | 71 | 5.0 V

Is the inspection result normal?
YES>>GO TO 3.
NO>>Replace AV control unit.
3.CHECK MICROPHONE SIGNAL

1. Connect microphone connector.
2. Check signal between AV control unit harness connector.

   (+) | (−) | Condition | Reference value
   AV control unit | AV control unit
   Connector | Terminal | Connector | Terminal
   M203 | 87 | M203 | 71 | Give a voice. |

Is the inspection result normal?
YES>>Replace AV control unit.
NO>>Replace microphone.