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

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. Check for DTCs and check if the same trouble occurs again.

   OK

   No DTCs are output.

NG → See step   4 

OK → END 

1. Disconnect the R65 multi-media interface ECU connector.
   Fig 1: Identifying R65 Multi-Media Interface ECU Connector Terminals

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   R65-7 (GND) - Body ground	Always	Below 1 Ω

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   R65-12 (+B) - Body ground	Always	11 to 14 V
   R65-11 (ACC) - Body ground	Engine switch on (ACC)	11 to 14 V

   TEXT IN ILLUSTRATION
   
   

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

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Disconnect the R65 multi-media interface ECU connector.
2. Disconnect the L114 display and navigation module display connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   R65-9 (TX1+) - L114-12 (TX2+)	Always	Below 1 Ω
   R65-10 (TX1-) - L114-13 (TX2-)	Always	Below 1 Ω
   R65-9 (TX1+) - Body ground	Always	10 kΩ or higher
   R65-10 (TX1-) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Temporarily replace the multi-media interface ECU with a new normally functioning one. Refer to REMOVAL .
2. Clear the DTCs. Refer to DTC CHECK / CLEAR .
3. Check for DTCs and check if the same trouble occurs again.

   OK

   No DTCs are output.

NG → See step   7 

OK → END