B278C

NETWORKING: LIN COMMUNICATION SYSTEM: B278C: Lost Communication with Power Source Control

DTC B278C - Lost Communication with Power Source Control

DESCRIPTION

This DTC is stored when LIN communication between the certification ECU (smart key ECU assembly) and power management control ECU stops for more than 10 seconds.





WIRING DIAGRAM





INSPECTION PROCEDURE
NOTICE:
- If the certification ECU (smart key ECU assembly) is replaced, register the key.
- When using the Techstream to troubleshoot with the ignition switch off:
Connect the Techstream to the DLC3, and turn the courtesy switch on and off at 1.5-second intervals until communication between the Techstream and vehicle begins.

PROCEDURE

1. CHECK HARNESS AND CONNECTOR (POWER MANAGEMENT CONTROL ECU - BATTERY AND BODY GROUND)




(a) Disconnect the D43 ECU connector.
(b) Measure the resistance and voltage according to the value(s) in the table below.
Standard Resistance:





Standard Voltage:





Text in Illustration





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

2. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - POWER MANAGEMENT CONTROL ECU)




(a) Disconnect the D25 ECU connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:





Text in Illustration





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

3. REPLACE POWER MANAGEMENT CONTROL ECU
(a) Replace the power management control ECU Removal.
NEXT -- Continue to next step.

4. CHECK DTC OUTPUT
(a) Clear the DTC Initial Inspection and Diagnostic Overview.
(b) Recheck for DTCs.
OK:
DTC B278C is not output.

NG -- REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)
OK -- END (POWER MANAGEMENT CONTROL ECU WAS DEFECTIVE)