DTC B156A: Gateway ECU Disconnected; DTC B1590: No Response from Gateway ECU: 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 network gateway ECU connector.
   Fig 1: Identifying J76 Connector End View

   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
   J76-24 (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
   J76-10 (BATT) - J76-24 (GND)	Always	11 to 14 V
   J76-2 (ACC) - J76-24 (GND)	Engine switch on (ACC)	11 to 14 V
   J76-1 (IG) - J76-24 (GND)	Engine switch on (IG)	11 to 14 V

   TEXT IN ILLUSTRATION
   
   

   *a	Front view of wire harness connector (to Network Gateway ECU)

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Disconnect the display and navigation module display connector.
2. Disconnect the network gateway ECU connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   J102-12 (TX2+) - J76-6 (GTX+)	Always	Below 1 Ω
   J102-13 (TX2-) - J76-21 (GTX-)	Always	Below 1 Ω
   J102-12 (TX2+) - Body ground	Always	10 kΩ or higher
   J102-13 (TX2-) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Replace the network gateway 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   7 

OK → END