B2785

DOOR LOCK: SMART KEY SYSTEM: B2785: Communication Malfunction between ECUs Connected by LIN
B2785 - Communication Malfunction between ECUs Connected by LIN

DESCRIPTION

The smart key system uses the LIN communication line for communication. LIN communication sends and receives signals by serial communication, and connects with CAN and multiplex communication via the gateway ECU.

The LIN communication bus directly uses battery power. It consists of a single wire which only uses the transceiver and pull-up resistance of the open-collector.

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1. RECONFIRM DTC

(a) Clear the DTC and repeat the procedure to re-check it Door Lock - Smart Key System.

OK:

DTC is not output.

OK -- END (SYSTEM IS NORMAL)
NG -- Continue to next step.

2. CHECK WIRE HARNESS (CERTIFICATION ECU - ID CODE BOX - POWER SOURCE CONTROL ECU)

(a) Disconnect the D14, D39 and D44 ECU connectors.

(b) Disconnect the D29 ID code box connector.

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

Resistance:

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

3. REPLACE CERTIFICATION ECU (CHECK OPERATION OF CERTIFICATION ECU)

(a) Replace the certification ECU.

(b) Clear the DTC and repeat the procedure to re-check it Door Lock - Smart Key System.

OK:

DTC is not output.

OK -- END (CERTIFICATION ECU IS DEFECTIVE)
NG -- Continue to next step.

4. REPLACE POWER SOURCE CONTROL ECU (CHECK OPERATION OF POWER SOURCE CONTROL ECU)

(a) Replace the power source control ECU.

(b) Clear the DTC and repeat the procedure to re-check it Door Lock - Smart Key System.

OK:

DTC is not output.

OK -- END (POWER SOURCE CONTROL ECU IS DEFECTIVE)
NG -- Continue to next step.

5. REPLACE STEERING LOCK ECU (CHECK OPERATION OF STEERING LOCK ECU)

(a) Replace the steering lock ECU.

(b) Clear the DTC and repeat the procedure to re-check it Door Lock - Smart Key System.

OK:

DTC is not output.

OK -- END (STEERING LOCK ECU IS DEFECTIVE)

NG -- REPLACE ID CODE BOX