B2785

MULTIPLEX COMMUNICATION: LIN COMMUNICATION SYSTEM: B2785: Communication Malfunction between ECUs Connected by LIN
B2785 - Communication Malfunction between ECUs Connected by LIN

DESCRIPTION

The certification ECU (smart key ECU) monitors the LIN communication bus between the components related to the certification intermittently. DTC B2785 is output when a malfunction in the LIN communication bus between the components related to the certification is detected continuously 3 times.





WIRING DIAGRAM





INSPECTION PROCEDURE

NOTICE:
When using the Techstream with the engine switch off to troubleshoot:

Connect the Techstream to the vehicle, and turn a courtesy switch on and off at 1.5 second intervals until communication between the Techstream and vehicle begins.

HINT
When DTC B2785 and B2287 are output simultaneously, perform the troubleshooting for DTC B2785 first.

PROCEDURE

1. CLEAR DTC

(a) Clear the DTC Reading and Clearing Diagnostic Trouble Codes.

NEXT -- Continue to next step.

2. CHECK FOR DTC

(a) Recheck for DTC Reading and Clearing Diagnostic Trouble Codes.

OK:

DTC B2785 is not output.

NG -- CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - MAIN BODY ECU)

OK -- USE SIMULATION METHOD TO CHECK How To Proceed With Troubleshooting

3. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - MAIN BODY ECU)

(a) Disconnect the L15 and DA ECU connectors.





(b) Measure the resistance and voltage according to the value(s) in the table below.

Standard resistance:





Standard voltage:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

4. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - BODY GROUND)

(a) Reconnect the DA ECU connector.





(b) Disconnect the L15 ECU connector.

(c) Measure the resistance and voltage according to the value(s) in the table below.

Standard resistance:





Standard voltage:





NG -- CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - BODY GROUND)

OK -- REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) Removal

5. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - BODY GROUND)

(a) Disconnect the DA ECU connector.





(b) Measure the resistance and voltage according to the value(s) in the table below.

Standard resistance:





Standard voltage:





NG -- CLEAR DTC

OK -- REPLACE MAIN BODY ECU (DRIVER SIDE JUNCTION BLOCK)

6. CLEAR DTC

(a) Reconnect the L15 ECU connector.

(b) Reconnect the DA ECU connector.

(c) Clear the DTC Reading and Clearing Diagnostic Trouble Codes.

NEXT -- Continue to next step.

7. CHECK FOR DTC

(a) Disconnect the L33 ECU connector.

(b) Recheck for DTC Reading and Clearing Diagnostic Trouble Codes.

Result





B -- REPLACE STEERING LOCK ACTUATOR ASSEMBLY (STEERING LOCK ECU) Disassembly
A -- Continue to next step.

8. CLEAR DTC

(a) Reconnect the L33 ECU connector.

(b) Clear the DTC Reading and Clearing Diagnostic Trouble Codes.

NEXT -- Continue to next step.

9. CHECK FOR DTC

(a) Disconnect the L32 box connector.

(b) Recheck for DTC Reading and Clearing Diagnostic Trouble Codes.

Result





B -- REPLACE ID CODE BOX (IMMOBILISER CODE ECU) Removal

A -- REPAIR OR REPLACE HARNESS OR CONNECTOR