B2785

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

DTC B2785 - Communication Malfunction between ECUs Connected by LIN

DESCRIPTION

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






WIRING DIAGRAM





INSPECTION PROCEDURE
NOTE: When using the intelligent tester or Techstream with the power switch OFF to troubleshoot:

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

Result:





B -- USE SIMULATION METHOD TO CHECK
A -- Continue to next step.
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
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
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
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
A -- REPAIR OR REPLACE HARNESS OR CONNECTOR