B2785

NETWORKING: 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) 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 ignition 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.

PROCEDURE

1. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU) - EACH ECU)





(a) Disconnect the D88 certification ECU (smart key ECU) connector.

(b) Disconnect the D29 steering lock actuator assembly (steering lock ECU) connector.

(c) Disconnect the D89 power management control ECU connector.

(d) Measure the resistance and voltage according to the value(s) in the tables below.

Standard Resistance (Check for Open):





Standard Resistance (Check for Short):





Standard Voltage:





Text in Illustration





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 D88 certification ECU (smart key ECU) and D89 steering lock actuator assembly (steering lock ECU) connectors.

(c) Check for DTCs.

Result





B -- REPLACE POWER MANAGEMENT CONTROL ECU
A -- Continue to next step.

3. CHECK FOR DTC

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

(b) Reconnect the D89 power management control ECU connector.

(c) Disconnect the D29 steering lock actuator assembly (steering lock ECU) connector.

(d) Check for DTCs.

Result





B -- REPLACE STEERING LOCK ACTUATOR ASSEMBLY (STEERING LOCK ECU)

A -- REPLACE CERTIFICATION ECU (SMART KEY ECU) Removal

4. REPLACE POWER MANAGEMENT CONTROL ECU

(a) Temporarily replace the power management control ECU with a new or normally functioning one.

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

NEXT -- Continue to next step.

5. CHECK FOR DTC

(a) Check for DTCs Reading and Clearing Diagnostic Trouble Codes.

Result





B -- REPLACE CERTIFICATION ECU (SMART KEY ECU) Removal

A -- END (POWER MANAGEMENT CONTROL ECU IS MALFUNCTIONING)

6. REPLACE STEERING LOCK ACTUATOR ASSEMBLY (STEERING LOCK ECU)

(a) Temporarily replace the steering lock actuator assembly (steering lock ECU) with a new or normally functioning one Removal.

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

NEXT -- Continue to next step.

7. CHECK FOR DTC

(a) Check for DTCs Reading and Clearing Diagnostic Trouble Codes.

Result





B -- REPLACE CERTIFICATION ECU (SMART KEY ECU) Removal

A -- END (STEERING LOCK ACTUATOR ASSEMBLY IS MALFUNCTIONING)