ENGINE IMMOBILISER SYSTEM, Diagnostic DTC:B278A

DTC Code DTC Name
B278A Short to GND in Immobiliser System Power Source Circuit

DESCRIPTION

This DTC is output when the power switch power source supply line is open or shorted.

DTC Code DTC Detection Condition Trouble Area
B278A Power switch power source supply line is open or shorted

  • Harness or connector


  • Power switch


  • Certification ECU

WIRING DIAGRAM

A01H1YEE06

INSPECTION PROCEDURE

PROCEDURE


  1. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - POWER SWITCH)

    A01H118E17

    1. Disconnect the L15 ECU connector.

    2. Disconnect the L36 switch connector.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      L15-30 (VC5) - L36-14 (VC5) Always Below 1 Ω
      L15-40 (AGND) - L36-8 (AGND)
      L15-30 (VC5) or L36-14 (VC5) - Body ground Always 10 kΩ or higher
      L15-40 (AGND) or L36-8 (AGND) - Body ground

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  2. REPLACE POWER SWITCH


    1. Temporarily replace the power switch with a new one Click here.


    NEXT

  3. CLEAR DTC


    1. Clear the DTC Click here.


    NEXT

  4. CHECK FOR DTC


    1. Recheck for DTC Click here.

      OK
      DTC B278A is not output.

    NG

    REPLACE CERTIFICATION ECU

    OK

    END (POWER SWITCH IS DEFECTIVE)