B2785

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

DTC B2785 - Communication Malfunction between ECUs Connected by LIN

DESCRIPTION

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

WIRING DIAGRAM

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

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

(a) Disconnect the 2D and E29 ECU connectors.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
2. CHECK FOR DTC
(a) Clear the DTC Reading and Clearing Diagnostic Trouble Codes.
(b) Reconnect the E29 ECU connector.
(c) Recheck for DTCs.

Result

B -- REPLACE MAIN BODY ECU (COWL PANEL JUNCTION BLOCK LH)
A -- Continue to next step.
3. CHECK FOR DTC
(a) Clear the DTC Reading and Clearing Diagnostic Trouble Codes.
(b) Reconnect the 2D ECU connector.
(c) Disconnect the E26 ECU connector.
(d) Recheck for DTCs.

Result

B -- REPLACE STEERING LOCK ECU (STEERING LOCK ACTUATOR ASSEMBLY)
A -- Continue to next step.
4. CHECK FOR DTC
(a) Clear the DTC Reading and Clearing Diagnostic Trouble Codes.
(b) Reconnect the E26 ECU connector.
(c) Disconnect the E28 box connector.
(d) Recheck for DTCs.

Result

B -- REPLACE ID CODE BOX (IMMOBILIZER CODE ECU)
A -- REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)
5. REPLACE MAIN BODY ECU (COWL PANEL JUNCTION BLOCK LH)
(a) Temporarily replace the main body ECU (cowl side junction block LH) with a new or normally functioning one.
(b) Clear the DTC Reading and Clearing Diagnostic Trouble Codes.
NEXT -- Continue to next step.
6. CHECK FOR DTC
(a) Recheck for DTCs.

Result

B -- REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)
A -- END (MAIN BODY ECU IS DEFECTIVE)
7. REPLACE STEERING LOCK ECU (STEERING LOCK ACTUATOR ASSEMBLY)
(a) Temporarily replace the steering lock ECU with a new or normally functioning one Disassembly.
(b) Clear the DTC Reading and Clearing Diagnostic Trouble Codes.
NEXT -- Continue to next step.
8. CHECK FOR DTC
(a) Recheck for DTCs.

Result

B -- REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)
A -- END (STEERING LOCK ECU IS DEFECTIVE)
9. REPLACE ID CODE BOX (IMMOBILIZER CODE ECU)
(a) Temporarily replace the ID code box (immobilizer code ECU) with a new or normally functioning one Removal.
(b) Clear the DTC Reading and Clearing Diagnostic Trouble Codes.
NEXT -- Continue to next step.
10. CHECK FOR DTC
(a) Recheck for DTCs Reading and Clearing Diagnostic Trouble Codes.

Result

B -- REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)
A -- END (ID CODE BOX IS DEFECTIVE)