LIN COMMUNICATION SYSTEM, Diagnostic DTC:B278C

DTC Code DTC Name
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 10 seconds or more.

DTC Code DTC Detection Condition Trouble Area
B278C No communication between the certification ECU (smart key ECU assembly) and power management control ECU for 10 seconds or more.

  • Power management control ECU

  • Certification ECU (smart key ECU assembly)

  • Harness or connector

WIRING DIAGRAM

A01FQ9TE01

INSPECTION PROCEDURE

Note


  • When using the GTS with the power switch off to troubleshoot:

    Connect the GTS to the vehicle, and turn a courtesy switch on and off at 1.5 seconds intervals until communication between the GTS and vehicle begins.

  • Inspect the fuses for circuits related to this system before performing the following inspection procedure.

  • Before replacing the certification ECU (smart key ECU assembly), refer to the entry and start system (for Entry Function) Click here.

PROCEDURE


  1. CLEAR DTC


    1. Clear the DTCs Click here.


    NEXT

  2. CHECK FOR DTC


    1. Check for DTCs Click here.

      Result
      Result Proceed to
      DTC B278C is output A
      DTC B278C is not output B

    B

    USE SIMULATION METHOD TO CHECK Click here

    A

  3. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU [SMART KEY ECU] - POWER MANAGEMENT CONTROL ECU)


    1. Disconnect the N95 certification ECU (smart key ECU assembly) connector.

    2. Disconnect the N92 power management control ECU connector.

      Standard Resistance
      Tester Connection Condition Specified Condition
      N95-12 (LIN) - N92-11 (LIN2) Always Below 1 Ω
      N95-12 (LIN) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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


    1. A01FTGFE01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Power Management Control ECU)

      Disconnect the power management control ECU connectors.

    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition
      N91-1 (AM22) - Body ground Always 11 to 14 V
      N92-7 (AM21) - Body ground Always 11 to 14 V

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      N91-6 (E1) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. REPLACE POWER MANAGEMENT CONTROL ECU


    1. Replace the power management control ECU with a new or normally functioning one Click here.


    NEXT

  6. CLEAR DTC


    1. Clear the DTCs Click here.


    NEXT

  7. CHECK FOR DTC


    1. Check for DTCs Click here.

      OK
      DTC B278C is not output.

    NG

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

    OK

    END (POWER MANAGEMENT CONTROL ECU IS DEFECTIVE)