DTC B2785: Communication Malfunction between ECUs Connected by LIN [10/2021 - 11/2023]: Procedure

1. Disconnect the H48 certification ECU (smart key ECU assembly) connector.
2. Disconnect the H53 ID code box (immobiliser code ECU) connector.
3. Measure the resistance according to the value(s) in the table below.
   NOTE:

   Make sure that each ECU is in sleep mode before performing the inspection. To enter sleep mode, turn the ignition switch from ON to off and wait for 180 seconds or more without operating any switches.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   H48-13 (LIN) - H53-2 (LIN1)	Ignition switch off	Below 1 Ω
   H48-13 (LIN) or H53-2 (LIN1) - Body ground	Ignition switch off	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  2

1. Connect the H48 certification ECU (smart key ECU assembly) connector.
2. Clear the DTCs.

   Body Electrical > Smart Key > Clear DTCs 

3. Recheck for DTCs.

   Body Electrical > Smart Key > Trouble Codes 

   Result

   Result	Proceed to
   DTC B2785 is output	A
   DTC B2785 is not output	B

Result: 

A 

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [12/2019 - 11/2023] 

Result: 

B 

REPLACE ID CODE BOX (IMMOBILISER CODE ECU). Refer to  REMOVAL [12/2019 - 10/2022]  , or refer to  REMOVAL [10/2022 - 11/2023]