Mute Signal Circuit between Radio Receiver and Multi-media Interface ECU: Procedure

1. Measure the voltage according to the value(s) in the table below.
   Fig 1: Inspecting Radio Receiver Assembly E79 Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   E79-6 (MUTE) - Body ground	Ignition switch ACC, USB audio system is playing → Changing modes	Above 3.5 V → Below 1 V

   TEXT IN ILLUSTRATION
   
   

   *a	Component with harness connected (Radio Receiver Assembly)

NG → See step   2 

OK → See step   4 

1. Disconnect the radio receiver assembly and multi-media interface ECU connectors.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   E79-6 (MUTE) - E77-6 (MUT1)	Always	Below 1 Ω
   E79-6 (MUTE) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Reconnect the multi-media interface ECU connector.
   Fig 2: Inspecting Multi-Media Interface ECU E77 Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   E77-6 (MUT1) - Body ground	Ignition switch ACC	Above 3.5 V

   TEXT IN ILLUSTRATION
   
   

   *a	Component with harness connected (Multi-media Interface ECU)

NG → See step   5 

OK → See step   6