DTC B156E: No Response from Multi-media Interface ECU; DTC B156B: Multi-media Interface ECU Disconnected: Procedure

1. Check for optional components.
   1. Check that optional components (including associated wiring) which generate radio waves are not installed.

      Result

      Result	Proceed to
      Optional components (including associated wiring) are installed.	A
      Optional components (including associated wiring) are not installed.	B

      HINT: 

      • Electrical noise from radio waves generated by optional components or the wiring for those components may affect AVC-LAN communication.
      • This DTC may be stored when an AVC-LAN communication error occurs due to electrical noise.

B → See step   3 

A: Go to next step 

1. Remove optional components (including associated wiring).
   NOTE:

   Do not remove optional components or associated wiring without the permission of the customer.

NEXT: Go to next step 

1. Clear the DTCs. Refer to DTC CHECK / CLEAR .
2. Recheck for DTCs and check if the same DTC is output again.

   OK

   No DTCs are output.

NG → See step   4 

OK → END 

1. Disconnect the U9 multi-media interface ECU connector.
   Fig 1: Identifying Multi-Media Interface ECU Connector

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Disconnect the G24 display and navigation module display connector.
   Fig 2: Identifying Display And Navigation Module Display Connector

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   U9-12 (+B) - G24-12 (+B)	Always	Below 1 Ω
   U9-11 (ACC) - G24-11 (ACC)	Always	Below 1 Ω
   U9-7 (GND) - G24-7 (GND)	Always	Below 1 Ω
   U9-9 (TX1+) - G24-9 (TXM+)	Always	Below 1 Ω
   U9-10 (TX1-) - G24-10 (TXM-)	Always	Below 1 Ω
   U9-12 (+B) - Body ground	Always	10 kΩ or higher
   U9-11 (ACC) - Body ground	Always	10 kΩ or higher
   U9-7 (GND) - Body ground	Always	10 kΩ or higher
   U9-9 (TX1+) - Body ground	Always	10 kΩ or higher
   U9-10 (TX1-) - Body ground	Always	10 kΩ or higher

   TEXT IN ILLUSTRATION
   
   

   *1	Front view of wire harness connector (to Multi-media Interface ECU)
   *2	Front view of wire harness connector (to Display and Navigation Module Display)

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Reconnect the G24 display and navigation module display connector.
2. Disconnect the U9 multi-media interface ECU connector.
   Fig 3: Identifying Multi-Media Interface ECU Connector

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   U9-7 (GND) - Body ground	Always	Below 1 Ω

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   U9-12 (+B) - U9-7 (GND)	Engine switch off	11 to 14 V
   U9-11 (ACC) - U9-7 (GND)	Engine switch on (ACC)	11 to 14 V

   TEXT IN ILLUSTRATION
   
   

   *1	Front view of wire harness connector (to Multi-media Interface ECU)

NG → See step   7 

OK: Go to next step 

1. Replace the multi-media interface ECU. Refer to REMOVAL .
2. Clear the DTCs. Refer to DTC CHECK / CLEAR .
3. Recheck for DTCs and check if the same DTC is output again.

   OK

   No DTCs are output.

NG → See step   8 

OK → END